WO2020138218A1 - Semiconductor device and production method - Google Patents

Semiconductor device and production method Download PDF

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Publication number
WO2020138218A1
WO2020138218A1 PCT/JP2019/050950 JP2019050950W WO2020138218A1 WO 2020138218 A1 WO2020138218 A1 WO 2020138218A1 JP 2019050950 W JP2019050950 W JP 2019050950W WO 2020138218 A1 WO2020138218 A1 WO 2020138218A1
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Prior art keywords
region
concentration
depth
hydrogen
semiconductor substrate
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PCT/JP2019/050950
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French (fr)
Japanese (ja)
Inventor
美佐稀 目黒
吉村　尚
博 瀧下
奈緒子 兒玉
泰典 阿形
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富士電機株式会社
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Application filed by 富士電機株式会社 filed Critical 富士電機株式会社
Priority to CN202410807463.2A priority Critical patent/CN118676194A/en
Priority to CN201980034474.9A priority patent/CN112204710B/en
Priority to DE112019002290.3T priority patent/DE112019002290T5/en
Priority to JP2020563375A priority patent/JP7099550B2/en
Publication of WO2020138218A1 publication Critical patent/WO2020138218A1/en
Priority to US17/106,187 priority patent/US11972950B2/en
Priority to JP2022105137A priority patent/JP7563425B2/en
Priority to US18/638,688 priority patent/US20240266176A1/en

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    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
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    • H01L21/2253—Diffusion into or out of group IV semiconductors using predeposition of impurities into the semiconductor surface, e.g. from a gaseous phase by ion implantation
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Definitions

  • the present invention relates to a semiconductor device and a manufacturing method.
  • Patent Document 1 Japanese Patent Publication No. 2016-204227
  • the range of the donor region and the donor concentration that are generated by the bonding of crystal defects and hydrogen can be accurately controlled.
  • a semiconductor device including a semiconductor substrate having an upper surface and a lower surface.
  • the hydrogen concentration distribution may have a hydrogen concentration peak in the depth direction connecting the upper surface and the lower surface of the semiconductor substrate.
  • the helium concentration distribution may have a helium concentration peak.
  • the donor concentration distribution may have a first donor concentration peak and a second donor concentration peak.
  • the hydrogen concentration peak and the first donor concentration peak may be arranged at the first depth.
  • the helium concentration peak and the second donor concentration peak may be arranged at a second depth deeper than the first depth with reference to the lower surface.
  • Each concentration peak may have an upward slope where the concentration value increases from the lower surface to the upper surface.
  • the value obtained by normalizing the slope of the upward slope of the second donor concentration peak by the slope of the slope of the helium concentration peak is the slope of the slope of the first donor concentration peak is the slope of the upward slope of the hydrogen concentration peak. It may be smaller than the standardized value.
  • each concentration peak may have a downward slope where the concentration value decreases from the lower surface toward the upper surface.
  • the slope of the ascending slope may be smaller than the slope of the descending slope.
  • the slope of the ascending slope may be smaller than the slope of the descending slope.
  • the donor concentration distribution between the first depth and the second depth may have a flat region where the donor concentration is almost constant.
  • the length of the flat region in the depth direction may be 10% or more of the thickness of the semiconductor substrate in the depth direction.
  • the donor concentration distribution between the first depth and the second depth may have a flat region where the donor concentration is almost constant.
  • the length of the flat region in the depth direction may be 10 ⁇ m or more.
  • the minimum donor concentration of the flat region may be higher than the donor concentration of the semiconductor substrate.
  • the minimum value of the donor concentration between the first depth and the second depth may be higher than the donor concentration of the semiconductor substrate.
  • the concentration value of the helium concentration peak may be smaller than the concentration value of the hydrogen concentration peak.
  • the semiconductor device may include an N-type drift region provided on the semiconductor substrate.
  • the semiconductor device may include an emitter region provided in contact with the upper surface of the semiconductor substrate and having a donor concentration higher than that of the drift region.
  • the semiconductor device may include a P-type base region provided between the emitter region and the drift region.
  • the semiconductor device may include a P-type collector region provided in contact with the lower surface of the semiconductor substrate.
  • An N-type buffer region, which is provided between the collector region and the drift region and has one or more donor concentration peaks having a higher donor concentration than the drift region, may be provided.
  • the first donor concentration peak may be a buffer region donor concentration peak.
  • the semiconductor device may include an accumulation region provided between the base region and the drift region and having one or more donor concentration peaks having a higher donor concentration than the drift region.
  • the second donor concentration peak may be the donor concentration peak of the accumulation region.
  • the accumulation region may have a donor concentration peak due to a donor other than hydrogen, in addition to the second donor concentration peak.
  • the second donor concentration peak may be arranged between the buffer area and the accumulation area.
  • the semiconductor device may include a gate trench portion provided on the upper surface of the semiconductor substrate.
  • the second donor concentration peak may be arranged between the bottom of the gate trench portion and the upper surface of the semiconductor substrate.
  • the semiconductor device may include an active part provided on the semiconductor substrate.
  • the semiconductor device may include an edge termination structure portion provided so as to surround the active portion in a top view of the semiconductor substrate.
  • the semiconductor substrate may have a passage region through which the injected helium passes at the position of the helium concentration peak. In the depth direction, the pass region provided in the edge termination structure may be shorter than the pass region provided in the active portion, or the pass region may not be provided in the edge termination structure.
  • the semiconductor device may include a transistor section and a diode section provided on the semiconductor substrate.
  • the pass region provided in the diode part may be shorter than the pass region provided in the transistor part, or the pass region may not be provided in the diode part.
  • the passage area provided in the transistor portion is shorter than the passage area provided in the diode portion, or the passage area may not be provided in the transistor portion.
  • the first depth may be included in a range of 5 ⁇ m or less from the lower surface in the depth direction.
  • the donor concentration at the hydrogen concentration peak may be 1 ⁇ 10 15 /cm 3 or more and 1 ⁇ 10 17 /cm 3 or less.
  • a semiconductor device including a semiconductor substrate having an upper surface and a lower surface.
  • the hydrogen concentration distribution in the depth direction connecting the upper surface and the lower surface of the semiconductor substrate is a hydrogen concentration peak arranged in the range of 5 ⁇ m or less in the depth direction from the lower surface, and a helium concentration arranged on the upper surface side of the hydrogen concentration peak. And a peak.
  • the semiconductor substrate has an impurity concentration peak between the lower surface and the hydrogen concentration peak, and the impurity may be argon or fluorine.
  • a third aspect of the present invention provides a method for manufacturing a semiconductor device according to the first aspect.
  • the manufacturing method may include a first implantation step of implanting hydrogen from the lower surface of the semiconductor substrate to the first depth.
  • the manufacturing method may include a second implantation step of implanting helium from the lower surface of the semiconductor substrate to a second depth to form a passage region through which helium has passed.
  • the manufacturing method may include a diffusion step in which the semiconductor substrate is heat-treated to diffuse the hydrogen implanted into the first depth into the passage region. In the semiconductor substrate heat-treated in the diffusion step, the dose amount of hydrogen in the first implantation step is set so that the minimum value of the donor concentration of the passage region is higher than the donor concentration of the semiconductor substrate before the implantation of hydrogen. Good.
  • hydrogen may be implanted at a dose amount that is equal to or higher than the minimum dose amount determined by the diffusion coefficient of hydrogen in the semiconductor substrate and the second depth.
  • the semiconductor substrate is a silicon substrate, and when the second depth from the lower surface is x (cm), the hydrogen dose Q (/cm 2 ) in the first implantation step may satisfy the following formula. Q ⁇ 1.6 ⁇ 10 13 ⁇ e 0.06x
  • hydrogen may be implanted to the first depth by plasma doping.
  • the lower surface of the semiconductor substrate may be ground.
  • the lower surface of the semiconductor substrate may be laser annealed.
  • FIG. 3 is a cross-sectional view showing an example of the semiconductor device 100.
  • FIG. The hydrogen concentration distribution, the helium concentration distribution, the donor concentration distribution, and the vacancy defect concentration distribution 175 in the depth direction are shown at the position indicated by the line AA in FIG. It is a figure explaining the relationship between the hydrogen concentration peak 131 and the 1st donor concentration peak 111. It is a figure explaining the relationship between the helium concentration peak 141 and the 2nd donor concentration peak 121. It is a figure explaining the inclination of the uphill slope 142. It is a figure explaining the other definition of the standardization of the inclination of the uphill slope 112. It is a figure explaining other definitions of standardization of the slope of uphill slope 122.
  • FIG. 3 is a diagram showing a structural example of a semiconductor device 100.
  • FIG. FIG. 7 is a diagram showing an example of carrier concentration distribution in the depth direction at the position of line BB in FIG. 6.
  • FIG. 6 is a diagram showing another structural example of the semiconductor device 100.
  • FIG. 9 is a diagram showing an example of a carrier concentration distribution in the depth direction at the position of line CC in FIG. 8. The hydrogen concentration distribution, the helium concentration distribution, and the carrier concentration distribution in the depth direction at the position indicated by the line AA in FIG. 1 are shown.
  • FIG. 5 is a diagram showing an arrangement example of each element on the upper surface 21 of the semiconductor substrate 10.
  • FIG. 12 is a diagram showing an example of a cc′ cross section in FIG.
  • FIG. 11 It is a figure which shows the other example of arrangement
  • FIG. It is a figure which shows the other example of arrangement
  • FIG. It is a figure which shows the other example of arrangement
  • FIG. It is a figure which shows the other example of arrangement
  • FIG. It is a figure which shows the other example of arrangement
  • FIG. It is a figure which shows the other example of arrangement
  • FIG. It is a figure which shows the other example of arrangement
  • FIG. It is a figure which shows the other example of arrangement
  • FIG. It is a figure which shows the other example of arrangement
  • FIG. 6 is a diagram illustrating a minimum film thickness M of the photoresist film 200 for preventing helium ions from entering the semiconductor substrate 10. It is a figure which shows the other example of arrangement
  • FIG. 3 is a diagram showing an example of a hydrogen chemical concentration distribution and an argon chemical concentration distribution in the vicinity of a hydrogen concentration peak 131.
  • FIG. 3 is a diagram showing an example of a hydrogen chemical concentration distribution and an argon chemical concentration distribution in the vicinity of a hydrogen concentration peak 131.
  • FIG. 6 is a diagram showing another structural example of the semiconductor device 100.
  • 30 shows an example of carrier concentration distribution, hydrogen chemical concentration distribution, and boron chemical concentration distribution in the DD line of FIG. 31 shows an example of the carrier concentration distribution, the hydrogen chemical concentration distribution, and the phosphorus chemical concentration distribution on the line EE of FIG.
  • FIG. 7 is a diagram showing a part of the method of manufacturing the semiconductor device 100.
  • FIG. 7 is a diagram showing a part of the method of manufacturing the semiconductor device 100.
  • An example of a step of implanting hydrogen ions to the first depth Z1 and implanting helium ions to the second depth Z2 in the lower surface side structure formation step will be shown.
  • Another example of the step of implanting hydrogen ions to the first depth Z1 and implanting helium ions to the second depth Z2 in the lower surface side structure formation step will be described.
  • one side in the direction parallel to the depth direction of the semiconductor substrate is called “upper” and the other side is called “lower”.
  • one surface is called the upper surface and the other surface is called the lower surface.
  • the “up” and “down” directions are not limited to the gravity direction or the direction when the semiconductor device is mounted.
  • orthogonal coordinate axes of the X axis, Y axis, and Z axis The Cartesian coordinate axes only specify the relative positions of the components and do not limit the specific directions.
  • the Z-axis does not limit the height direction to the ground.
  • the +Z axis direction and the ⁇ Z axis direction are directions opposite to each other. When the positive and negative signs are not described and the Z axis direction is described, it means a direction parallel to the +Z axis and the ⁇ Z axis.
  • the chemical concentration refers to the concentration of impurities measured regardless of the activation state.
  • the chemical concentration can be measured by, for example, secondary ion mass spectrometry (SIMS).
  • SIMS secondary ion mass spectrometry
  • the concentration difference between the donor and the acceptor may be the concentration of the larger one of the donor and the acceptor.
  • the concentration difference can be measured by a voltage-capacitance measuring method (CV method).
  • the carrier concentration measured by the spread resistance measuring method (SR) may be the concentration of the donor or the acceptor.
  • the concentration distribution of the donor or the acceptor has a peak
  • the peak value may be the concentration of the donor or the acceptor in the region.
  • the average value of the donor or acceptor concentration in the region may be the donor or acceptor concentration.
  • Unit systems herein are SI unit systems unless otherwise noted. Although the unit of length may be displayed in cm, various calculations may be performed after converting to meters (m).
  • FIG. 1 is a sectional view showing an example of a semiconductor device 100.
  • the semiconductor device 100 includes a semiconductor substrate 10.
  • the semiconductor substrate 10 is a substrate made of a semiconductor material.
  • the semiconductor substrate 10 is a silicon substrate.
  • the semiconductor substrate 10 has a donor concentration that is determined by impurities and the like that are injected at the time of manufacturing.
  • the conductivity type of the semiconductor substrate 10 of this example is N-type.
  • the donor concentration in the semiconductor substrate 10 may be referred to as the substrate concentration.
  • the semiconductor substrate 10 has an upper surface 21 and a lower surface 23.
  • the upper surface 21 and the lower surface 23 are two main surfaces of the semiconductor substrate 10.
  • the orthogonal axes in the plane parallel to the upper surface 21 and the lower surface 23 are the X axis and the Y axis
  • the axis perpendicular to the upper surface 21 and the lower surface 23 is the Z axis.
  • semiconductor elements such as IGBT and FWD are formed on the semiconductor substrate 10, these element structures are omitted in FIG.
  • Hydrogen ions and helium ions are implanted into the semiconductor substrate 10 from the lower surface 23 side.
  • the hydrogen ion in this example is a proton.
  • Hydrogen ions are implanted to a depth Z1 in the depth direction (Z axis direction) of the semiconductor substrate 10.
  • Helium ions are implanted at the depth Z2.
  • the one closer to the lower surface 23 is the first depth Z1 and the one deeper than the first depth Z1 when viewed from the lower surface 23 is the second depth Z2.
  • the injected hydrogen and helium are schematically shown by X, but hydrogen and helium are also distributed around the injection positions Z1 and Z2.
  • the first depth Z1 may be arranged on the lower surface 23 side in the depth direction of the semiconductor substrate 10.
  • the first depth Z1 may be arranged in the range of half the thickness of the semiconductor substrate 10 or less with respect to the lower surface 23, and may be arranged in the range of 1 ⁇ 4 or less of the thickness of the semiconductor substrate 10. Good.
  • the second depth Z2 may be arranged on the upper surface 21 side in the depth direction of the semiconductor substrate 10.
  • the second depth Z2 may be arranged in the range of half or less of the thickness of the semiconductor substrate 10 with the upper surface 21 as a reference, and may be arranged in the range of 1 ⁇ 4 or less of the thickness of the semiconductor substrate 10. Good.
  • the first depth Z1 and the second depth Z2 are not limited to these ranges.
  • the helium ions implanted to the second depth Z2 pass through the passage region 106 from the lower surface 23 to the second depth Z2.
  • vacancy defects such as vacancies (V) and compound vacancies (VV) occur due to the passage of helium ions.
  • the pores include double pores unless otherwise specified.
  • the void density in the passage region 106 can be adjusted by the dose amount of the helium ions implanted into the second depth Z2.
  • VOH defects are formed by the bonding of vacancies (V) existing in the passage region 106 and oxygen (O) with hydrogen (H).
  • the VOH defect functions as a donor that supplies electrons.
  • the donor concentration of the passage region 106 can be made higher than the donor concentration Db (or the specific resistance or the base doping concentration) at the time of manufacturing the semiconductor ingot which is the base of the semiconductor substrate 10. Therefore, the donor concentration of the semiconductor substrate 10 can be easily adjusted according to the characteristics that the element formed on the semiconductor substrate 10 should have.
  • VOH defects having a distribution similar to the chemical concentration distribution of hydrogen and VOH defects similar to the distribution of vacancy defects in the passage region 106 are used as hydrogen donors or donors. Of hydrogen.
  • the dopant for setting the base doping concentration Db is a dopant added at the time of manufacturing a semiconductor ingot.
  • the semiconductor ingot is silicon
  • n-type may be phosphorus, antimony, or arsenic
  • p-type may be boron, aluminum, or the like.
  • the respective dopants may be used.
  • the method for manufacturing the semiconductor ingot may be any of the float zone (FZ) method, the Czochralski (CZ) method, and the magnetic field application Czochralski (MCZ) method.
  • the semiconductor substrate 10 having the base doping concentration Db must be prepared in accordance with the characteristics of the element to be formed on the semiconductor substrate 10, particularly the rated voltage or the breakdown voltage.
  • the semiconductor device 100 shown in FIG. 1 by controlling the dose amount and implantation depth of hydrogen ions and helium ions, the donor concentration and the passage region of the semiconductor substrate 10 when the semiconductor device 100 is completed.
  • the range of 106 can be partially higher than the base doping concentration Db. Therefore, even if the semiconductor substrate 10 having different base doping concentrations is used, an element having a predetermined rated voltage or withstand voltage characteristic can be formed.
  • the dose amounts of hydrogen ions and helium ions can be controlled with relatively high accuracy. Therefore, the concentration of vacancies (V) generated by implanting helium ions can be controlled with high precision, and the donor concentration of the passage region 106 can be controlled with high precision.
  • FIG. 2 shows the hydrogen concentration distribution, the helium concentration distribution, the donor concentration distribution, and the vacancy defect concentration distribution 175 in the depth direction at the position shown by the line AA in FIG.
  • the horizontal axis of FIG. 2 represents the depth position from the lower surface 23, and the vertical axis represents the hydrogen concentration, the helium concentration, the donor concentration, and the vacancy defect concentration per unit volume on the logarithmic axis.
  • the vacancy defect concentration distribution 175 is a distribution immediately after ion implantation of hydrogen ions and helium ions. When the semiconductor device 100 is completed, vacancies are reduced or disappeared as compared with immediately after the ion implantation, and the concentration distribution different from that in FIG. 2 is shown.
  • the donor concentration in FIG. 2 is an electrically activated doping concentration measured by, for example, the CV method or the SR method.
  • the hydrogen concentration distribution, the helium concentration distribution, and the vacancy defect concentration distribution 175 are shown by broken lines, and the donor concentration distribution is shown by a solid line.
  • the hydrogen concentration distribution has a hydrogen concentration peak 131.
  • the helium concentration distribution has a helium concentration peak 141.
  • the hydrogen concentration peak 131 has a maximum value at the first depth Z1.
  • the helium concentration peak 141 has a maximum value at the second depth Z2.
  • the donor concentration distribution has a first donor concentration peak 111 and a second donor concentration peak 121.
  • the first donor concentration peak 111 has a maximum value at the first depth Z1.
  • the second donor concentration peak 121 has a maximum value at the second depth Z2.
  • the position where the first donor concentration peak 111 has the maximum value does not have to be exactly the same as the first depth Z1.
  • the first donor concentration peak 111 may be disposed substantially at the first depth Z1.
  • the second donor concentration peak 121 is increased.
  • the peak 121 may be located substantially at the second depth Z2.
  • the vacancy defect concentration distribution 175 has a first vacancy concentration peak corresponding to the hydrogen concentration peak 131 and a second vacancy concentration peak (vacancy concentration peak 171) corresponding to the helium concentration peak 141. However, illustration of the first vacancy concentration peak is omitted.
  • the vacancy concentration peak 171 has a maximum value at the second depth Z2.
  • Each concentration peak has an upward slope in which the concentration value increases and a downward slope in which the concentration value decreases from the lower surface 23 to the upper surface 21 of the semiconductor substrate 10.
  • the hydrogen concentration peak 131 has an upslope 132 and a downslope 133.
  • the helium concentration peak 141 has an upslope 142 and a downslope 143.
  • the first donor concentration peak 111 has an upslope 112 and a downslope 113.
  • the second donor concentration peak 121 has an upslope 122 and a downslope 123.
  • the vacancy concentration peak 171 has an upslope 172 and a downslope 173.
  • the donor existing in the semiconductor substrate 10 before the implantation of hydrogen ions that is, the base doping concentration (concentration Db), the donor in which the implanted hydrogen is activated, and the VOH defect described above. And are included.
  • concentration Db concentration of hydrogen ions
  • the rate at which hydrogen is activated as a donor is, for example, about 1%.
  • the donor by the VOH defect corresponding to the vacancy defect concentration is more than the donor by the VOH defect corresponding to the hydrogen chemical concentration.
  • the donor concentration is rate-limited by the concentration of vacancy defects.
  • the VOH defect corresponding to the hydrogen chemical concentration refers to a VOH defect in which the hydrogen chemical concentration is more dominant than the vacancy defect concentration.
  • the VOH defect corresponding to the vacancy defect concentration refers to a VOH defect in which the vacancy defect concentration is more dominant than the hydrogen chemical concentration.
  • the VOH defects in which the hydrogen chemical concentration distribution is dominant have the following meanings.
  • the distribution of the donor concentration due to the VOH defects is the distribution of the hydrogen chemical concentration. Is similar to. As an example, it can be said that when the hydrogen chemical concentration is higher than the vacancy defect concentration at a certain depth and in the vicinity thereof, the hydrogen chemical concentration distribution becomes the dominant VOH defect donor concentration distribution.
  • a VOH defect in which the vacancy defect concentration distribution 175 is dominant means that the distribution of the donor concentration due to the VOH defect is similar to the distribution of the vacancy defect concentration because the vacancy defect concentration is sufficiently higher than the hydrogen chemical concentration. Is shown. As an example, it can be said that the vacancy defect concentration distribution 175 becomes the dominant VOH defect donor concentration distribution when the vacancy defect concentration is higher than the hydrogen chemical concentration at a certain depth and in the vicinity thereof.
  • holes (V, VV, etc.) generated by passage of hydrogen have depths as shown in FIG. It is considered that the distribution is almost uniform in the direction. In addition, it is considered that oxygen (O) that is injected at the time of manufacturing the semiconductor substrate 10 is evenly distributed in the depth direction. In addition, since hydrogen of the hydrogen concentration peak 131 diffuses in the passage region 106, a sufficient amount of hydrogen exists. These form a flat donor distribution as VOH defects.
  • the passage region 106 other than the vicinity of the first depth Z1 and the second depth Z2 there is a flat region 150 in which VOH defects functioning as donors are distributed almost uniformly.
  • the donor concentration distribution in the flat region 150 is almost constant in the depth direction.
  • the donor concentration being substantially constant in the depth direction means, for example, that a region where the difference between the maximum value and the minimum value of the donor concentration is within 50% of the maximum value of the donor concentration is continuous in the depth direction. You can point.
  • the difference may be 30% or less of the maximum value of the donor concentration of the region, and may be 10% or less.
  • the value of the donor concentration distribution may be within ⁇ 50% of the average concentration of the donor concentration distribution in a predetermined range in the depth direction, or within ⁇ 30% of the average concentration of the donor concentration distribution. Well, it may be within ⁇ 10%.
  • the predetermined range in the depth direction may be as follows as an example. That is, assuming that the length from the first depth Z1 to the second depth Z2 is Z L , from the center Zc between Z1 and Z2, the first depth Z1 side and the second depth Z2 side Further, a section having a length of 0.5Z L between two points separated by 0.25Z may be set as the range. Depending on the length of the flat region 150, the length of the predetermined range may be a 0.75Z L, may be a 0.3Z L, it may be 0.9Z L.
  • the range in which the flat region 150 is provided can be controlled by the position of the helium concentration peak 141.
  • the flat region 150 is provided between the hydrogen concentration peak 131 and the helium concentration peak 141.
  • the donor concentration of the flat region 150 can be controlled by the dose amount of helium ions at the helium concentration peak 141. By increasing the dose amount of helium ions, the number of vacancies (V) generated in the passage region 106 increases and the donor concentration increases.
  • the acceleration energy of the helium ions may be increased to a value at which the helium ions penetrate (penetrate) the semiconductor substrate 10. That is, the helium concentration peak 141 may not be left on the semiconductor substrate 10. Thereby, it is possible to increase the concentration of vacancy defects.
  • the acceleration energy is excessively large, the substrate may be damaged too much during the ion implantation, and the flatness may not be maintained in the distribution of the vacancy defects in the passage region 106. Therefore, the helium concentration peak 141 may be located inside the semiconductor substrate 10.
  • the second donor concentration peak 121 also tends to have a larger peak spread than the first donor concentration peak 111. That is, the second donor concentration peak 121 tends to be a gentler peak than the first donor concentration peak 111.
  • the concentration value of the hydrogen concentration peak 131 is larger than the concentration value of the helium concentration peak 141.
  • the concentration value of the hydrogen concentration peak 131 may be 10 times or more the concentration value of the helium concentration peak 141, or may be 100 times or more. In another example, the concentration value of the hydrogen concentration peak 131 may be equal to or lower than the concentration value of the helium concentration peak 141.
  • the concentration value of the hydrogen concentration peak 131 is high, the amount of hydrogen activated as a donor in the hydrogen concentration peak 131 is relatively large.
  • the ratio of donors of VOH defects whose hydrogen chemical concentration distribution is dominant is higher than that of the vacancy defect concentration distribution 175.
  • the shape of the first donor concentration peak 111 is similar to the shape of the hydrogen concentration peak 131.
  • the helium concentration peak 141 is apart from the hydrogen concentration peak 131, the amount of hydrogen activated as a donor at the helium concentration peak 141 is small. That is, the ratio of VOH defect donors in which the vacancy defect concentration distribution 175 is dominant is relatively higher than that of VOH defect donors in which the hydrogen chemical concentration distribution is dominant.
  • the similarity between the shape of the second donor concentration peak 121 and the shape of the helium concentration peak 141 is smaller than the similarity between the shape of the first donor concentration peak 111 and the shape of the hydrogen concentration peak 131. .. Since it is considered that the VOH defects are distributed almost uniformly in most of the passage region 106, the second donor concentration peak 121 has a more gentle shape.
  • the similarity of the peak shapes may be an index showing a smaller value as the difference in slope of the corresponding slope between the hydrogen concentration peak or the helium concentration peak and the donor concentration peak increases.
  • the flat region 150 can be provided between the first depth Z1 and the second depth Z2.
  • the length of the flat region 150 in the depth direction may be 10% or more, 30% or more, and 50% or more of the thickness of the semiconductor substrate 10 in the depth direction.
  • the length of the flat region 150 in the depth direction may be 10 ⁇ m or more, 30 ⁇ m or more, 50 ⁇ m or more, and 100 ⁇ m or more.
  • the minimum donor concentration of the flat region 150 may be higher than the base doping concentration Db of the semiconductor substrate 10. That is, the donor concentration of the flat region 150 may be higher than the base doping concentration Db over the entire flat region 150.
  • the difference between the donor concentration of the flat region 150 and the base doping concentration Db of the semiconductor substrate 10 can be adjusted by the helium dose amount at the helium concentration peak 141, for example.
  • the minimum value of the donor concentration between the first depth Z1 and the second depth Z2 may be higher than the base doping concentration of the semiconductor substrate 10.
  • An N-type region may be continuously provided between the hydrogen concentration peak 131 and the helium concentration peak 141. Further, the minimum value of the donor concentration between the second depth Z2 and the lower surface 23 of the semiconductor substrate 10 may be higher than the donor concentration of the semiconductor substrate 10.
  • FIG. 3A is a diagram illustrating the relationship between the hydrogen concentration peak 131 and the first donor concentration peak 111.
  • the slope 134 of the upward slope 132 of the hydrogen concentration peak 131 is used to normalize the slope 114 of the upward slope 112 of the first donor concentration peak 111.
  • the normalization is a process of dividing the slope 114 by the slope 134 as an example.
  • the inclination may be used to mean the absolute value of the inclination.
  • the slope of the ascending slope may be the slope between the position where the concentration has a maximum value and the position where the concentration has a predetermined ratio with respect to the maximum value.
  • the predetermined ratio may be 80%, 50%, 10%, 1% and other ratios may be used.
  • the slope 134 of the hydrogen concentration peak 131 is given by (H1-aH1)/(Z1-Z3), and the slope 114 of the first donor concentration peak 111 is (D1-aD1)/(Z1- Z4) is given.
  • H1 is the hydrogen concentration at the first depth Z1
  • D1 is the donor concentration at the first depth Z1
  • a is a predetermined ratio
  • Z3 is hydrogen at the up slope 132 of the hydrogen concentration peak 131.
  • the concentration is a depth at which the donor concentration is aH1
  • Z4 is the depth at which the donor concentration is aD1 in the upslope 112 of the first donor concentration peak 111.
  • the slope 114 is standardized by the slope 134, it becomes (D1-aD1)(Z1-Z3)/ ⁇ (H1-aH1)(Z1-Z4) ⁇ .
  • the inclination obtained by normalizing the inclination 114 with the inclination 134 is ⁇ .
  • FIG. 3B is a diagram illustrating the relationship between the helium concentration peak 141 and the second donor concentration peak 121.
  • the slope 144 of the upward slope 142 of the helium concentration peak 141 is used to standardize the slope 124 of the upward slope 122 of the second donor concentration peak 121.
  • the slope 144 of the helium concentration peak 141 is given by (H2-aH2)/(Z2-Z5), and the slope 124 of the second donor concentration peak 121 is (D2-aD2)/(Z2- Z6).
  • H2 is the helium concentration at the second depth Z2
  • D2 is the donor concentration at the second depth Z2
  • a is a predetermined ratio
  • Z5 is helium at the upward slope 142 of the helium concentration peak 141.
  • the concentration is a depth at which the donor concentration becomes aH2
  • Z6 is the depth at which the donor concentration becomes aD2 in the upward slope 122 of the second donor concentration peak 121.
  • the ratio a used to normalize the slope of the second donor concentration peak 121 may be the same as or different from the ratio a used to normalize the slope of the first donor concentration peak 111. ..
  • the slope 124 when the slope 124 is standardized by the slope 144, it becomes (D2-aD2)(Z2-Z5)/ ⁇ (Z2-Z6)(H2-aH2) ⁇ .
  • ⁇ be the slope obtained by normalizing the slope 124 with the slope 144.
  • the standardized slope ⁇ of the upward slope 122 of the second donor concentration peak 121 is smaller than the standardized slope ⁇ of the upward slope 112 of the first donor concentration peak 111. That is, the second donor concentration peak 121 is a gentler peak with respect to the concentration peak of hydrogen or helium than the first donor concentration peak 111.
  • the flat region 150 can be formed by implanting hydrogen ions and helium ions so that the second donor concentration peak 121 is formed. Further, by making the second donor concentration peak 121 have a gentle shape, it is possible to moderate the change in the donor concentration at the tip of the flat region 150.
  • the normalized slope ⁇ of the upslope 122 of the second donor concentration peak 121 may be less than or equal to 1 times the normalized slope ⁇ of the upslope 112 of the first donor concentration peak 111, 0.1 It may be less than or equal to double, or less than or equal to 0.01.
  • the slope 144 of the upward slope 142 of the helium concentration peak 141 may be smaller than the slope 145 of the downward slope 143. Since the concentration distribution of the helium ions implanted at a deep position from the lower surface 23 may have a gentle skirt on the lower surface 23 side, by comparing the slope 144 of the ascending slope 142 and the slope 145 of the descending slope 143, It may be possible to determine whether or not the helium of the helium concentration peak 141 is injected from the lower surface 23 side.
  • the slope 145 is given by (H2-aH2)/(Z7-Z2).
  • the slope 125 is given by (D2-aD2)/(Z7-Z2). Note that in FIG.
  • the slope 124 of the upward slope 122 of the second donor concentration peak 121 is larger than the slope 125 of the downward slope 123, but like the helium concentration peak 141, the upward slope of the second donor concentration peak 121.
  • the slope 124 of the slope 122 may be smaller than the slope 125 of the down slope 123.
  • FIG. 3C is a diagram illustrating the slope of the uphill slope 142.
  • the slope of the ascending slope 142 may be considered as follows. As shown in FIG. 3C, in the helium concentration peak 141, the width (10% full width) between the two positions Z8 and Z9 at which the concentration becomes 10% (0.1 ⁇ H2) of the peak concentration H2, FW 10%M.
  • the two positions Z8 and Z9 are the two positions closest to the peak position Z2 among the points where the helium concentration is 0.1 ⁇ H2 with the peak position Z2 sandwiched therebetween.
  • the position on the hydrogen concentration peak side of the two positions Z8 and Z9 is Z8.
  • the slope of the donor concentration at the position Z8 is almost flat.
  • the slope of the helium concentration at the position Z8 exceeds 100 times the slope of the donor concentration at the position Z8.
  • the slope of the helium concentration at the position Z8 may be 100 times or more the slope of the donor concentration at the position Z8, and may be 1000 times or more.
  • FIG. 4A is a diagram illustrating another definition of standardization of the slope of the upslope 112. In normalizing the slope of the upslope 112, for example, the following index ⁇ is introduced.
  • the position Z3 is a predetermined position here.
  • the position Z3 may be a position where the hydrogen concentration distribution and the donor concentration distribution have the upward slopes 132 and 112 on the lower surface side with respect to the position Z1.
  • the hydrogen concentration at position Z3 is a ⁇ H1, and the donor concentration is b ⁇ D1.
  • a is the ratio of the hydrogen concentration at the position Z3 to the concentration H1 of the hydrogen concentration peak 131 at the position Z1.
  • b is the ratio of the donor concentration at the position Z3 to the concentration D1 of the first donor concentration peak 111 at the position Z1.
  • the ratio of the slopes of the hydrogen concentration and the donor concentration in the sections Z3 to Z1 and the slope ratio ⁇ that normalizes the ratio of the slopes are introduced.
  • the ratio of the slope of the hydrogen concentration in the section Z3 to Z1 is defined as (H1/aH1)/(Z1-Z3).
  • the ratio of the gradient of the donor concentration in the sections Z3 to Z1 is defined as (D1/bD1)/(Z1-Z3).
  • the gradient ratio ⁇ obtained by normalizing the gradient ratio of the donor concentration by the gradient ratio of the hydrogen concentration in the sections Z3 to Z1 is ⁇ (D1/bD1)/(Z1-Z3) ⁇ / ⁇ (H1/aH1) /(Z1-Z3) ⁇ .
  • the normalized slope ratio ⁇ becomes a simple ratio a/b by calculating the above equation.
  • FIG. 4B is a diagram illustrating another definition of standardization of the slope of the upslope 122.
  • an index ⁇ similar to the index ⁇ is introduced.
  • the position Z5 is a predetermined position here.
  • the position Z5 may be a position where the helium concentration distribution and the donor concentration distribution are the up slopes 142 and 122 on the lower surface side of the position Z2.
  • the helium concentration at the position Z5 is c ⁇ H2, and the donor concentration is d ⁇ D2.
  • c is the ratio of the helium concentration at position Z5 to the concentration H2 of the helium concentration peak 141 at position Z2.
  • d is the ratio of the donor concentration at the position Z5 to the concentration D2 of the second donor concentration peak 121 at the position Z1.
  • the ratio of the helium concentration gradients in the sections Z5 to Z2 is defined as (H2/cH2)/(Z2-Z5).
  • the ratio of the gradients of the donor concentrations in the sections Z5 to Z2 is defined as (D2/dD2)/(Z2-Z5).
  • the slope ratio ⁇ obtained by normalizing the slope ratio of the donor concentration by the slope ratio of the helium concentration in the sections Z5 to Z2 is ⁇ (D2/dD2)/(Z2-Z5) ⁇ / ⁇ (H2/cH2) /(Z2-Z5) ⁇ .
  • the normalized slope ratio ⁇ becomes a simple ratio c/d by calculating the above equation.
  • the hydrogen concentration distribution and the donor concentration distribution often have similar shapes.
  • having a similar shape means that the donor concentration distribution shows a distribution that reflects the hydrogen concentration distribution, where the horizontal axis is the depth and the vertical axis is the common logarithm of the concentration. That is, in the predetermined section Z3 to Z1, by implanting hydrogen ions and further performing thermal annealing, the donor concentration distribution becomes a distribution that reflects the hydrogen concentration distribution.
  • H1 of the hydrogen concentration peak 131 is 1 ⁇ 10 17 atms/cm 3 and the hydrogen concentration aH1 at the position Z3 is 2 ⁇ 10 16 atms/cm 3 , a is 0.2.
  • the helium concentration distribution and the donor concentration distribution do not have to have similar shapes. That is, the donor concentration distribution does not have to reflect the helium concentration distribution in the predetermined sections Z5 to Z2.
  • H2 of the helium concentration peak 141 is 1 ⁇ 10 16 atms/cm 3 and helium concentration cH2 at the position Z5 is 1 ⁇ 10 15 atms/cm 3 , c is 0.1.
  • the normalized inclination ratio ⁇ is 0.2 because it is c/d. That is, at the position Z2 deep enough from the lower surface, the helium concentration distribution slope ratio c is 0.2 times the donor concentration distribution slope ratio d, indicating that the helium concentration distribution has a shape different from the similarity. I can say.
  • ⁇ is close to 1 when the peak position of the helium concentration distribution is near the bottom surface, and ⁇ is more than 1 when the peak position of the helium concentration distribution is sufficiently deep from the bottom surface.
  • the value may be small enough. That is, the normalized slope ratio ⁇ may be smaller than the normalized slope ratio ⁇ . Further, the slope ratio ⁇ may be 0.9 or less, 0.5 or less, and 0.2 or less. Alternatively, it may be 0.1 or less, or 0.01 or less.
  • the second donor concentration peak 121 when the carrier mobility is lowered, the donor concentration calculated from the spreading resistance, that is, the carrier concentration is lower than the carrier concentrations at the front and rear positions at the depth position Z2.
  • the ascending slope 122 has a decreasing slope, and therefore d has a negative sign. That is, d is a negative number whose absolute value is 1 or more.
  • ⁇ becomes a negative number. That is, the normalized slope ratio ⁇ may be smaller than the normalized slope ratio ⁇ . Further, the slope ratio ⁇ may be 0.9 or less, 0 or less, or ⁇ 1 or less. Alternatively, it may be ⁇ 10 or less and ⁇ 100 or less.
  • the actual position of the helium concentration peak 141 and the actual position of the second donor concentration peak 121 may be different.
  • the position of the hydrogen concentration peak 131 and the position of the first donor concentration peak 111 may not be exactly the same.
  • the concentration of the hydrogen or helium concentration at the peak position may be used as the peak position for convenience. This allows the calculation according to the above definition.
  • the helium concentration peak 141 has a maximum value. That is, the helium concentration distribution has a maximum value at the depth Z2. Since the helium concentration peak 141 has the maximum value, it is possible to compare the normalized slope ratios.
  • FIG. 5 is a diagram illustrating the flat area 150.
  • the flat region 150 is a region where the region where the donor concentration is between a predetermined maximum value max and a predetermined minimum value min is continuous in the depth direction.
  • the maximum value max the maximum value of the donor concentration in the region may be used.
  • the minimum value min may be a value of 50% of the maximum value max, a value of 70%, or a value of 90%.
  • the value of the donor concentration distribution may be within ⁇ 50% of the average concentration of the donor concentration distribution with respect to the average concentration of the donor concentration distribution in a predetermined range in the depth direction, and ⁇ 30%. %, and ⁇ 10%.
  • the predetermined range in the depth direction may be the same as described above.
  • FIG. 6 is a diagram showing a structural example of the semiconductor device 100.
  • the semiconductor device 100 of this example functions as an IGBT.
  • the semiconductor device 100 of this example has a semiconductor substrate 10, an interlayer insulating film 38, an emitter electrode 52, and a collector electrode 54.
  • the interlayer insulating film 38 is formed so as to cover at least a part of the upper surface 21 of the semiconductor substrate 10. Through holes such as contact holes are formed in the interlayer insulating film 38. The upper surface 21 of the semiconductor substrate 10 is exposed by the contact hole.
  • the interlayer insulating film 38 may be silicate glass such as PSG and BPSG, and may be an oxide film or a nitride film.
  • the emitter electrode 52 is formed on the upper surfaces of the semiconductor substrate 10 and the interlayer insulating film 38.
  • the emitter electrode 52 is also formed inside the contact hole and is in contact with the upper surface 21 of the semiconductor substrate 10 exposed by the contact hole.
  • the collector electrode 54 is formed on the lower surface 23 of the semiconductor substrate 10.
  • the collector electrode 54 may contact the entire lower surface 23 of the semiconductor substrate 10.
  • the emitter electrode 52 and the collector electrode 54 are formed of a metal material such as aluminum.
  • Collector region 22 is provided.
  • the emitter region 12 is provided in contact with the upper surface 21 of the semiconductor substrate 10 and has a higher donor concentration than the drift region 18.
  • the emitter region 12 contains an N-type impurity such as phosphorus.
  • the base region 14 is provided between the emitter region 12 and the drift region 18.
  • the base region 14 contains a P-type impurity such as boron.
  • P-type contact regions (not shown) alternately arranged with the emitter regions 12 are provided.
  • the contact region is formed on the upper surface 21 of the base region and may be formed deeper than the emitter region 12. The contact region suppresses the latch-up of the IGBT at turn-off.
  • the storage region 16 is provided between the base region 14 and the drift region 18, and has one or more donor concentration peaks having a higher donor concentration than the drift region 18.
  • the storage region 16 may contain N-type impurities such as phosphorus, and may contain hydrogen.
  • the collector region 22 is provided in contact with the lower surface 23 of the semiconductor substrate 10.
  • the acceptor concentration in the collector region 22 may be higher than the acceptor concentration in the base region 14.
  • the collector region 22 may contain the same P-type impurity as the base region 14 or may contain different P-type impurities.
  • the buffer region 20 is provided between the collector region 22 and the drift region 18, and has one or more donor concentration peaks having a higher donor concentration than the drift region 18.
  • the buffer region 20 has an N-type impurity such as hydrogen.
  • the buffer region 20 may function as a field stop layer that prevents the depletion layer spreading from the lower surface side of the base region 14 from reaching the collector region 22.
  • the gate trench section 40 reaches the drift region 18 from the upper surface 21 of the semiconductor substrate 10 through the emitter region 12, the base region 14 and the storage region 16.
  • the accumulation region 16 of this example is arranged above the lower end of the gate trench portion 40.
  • the storage region 16 may be provided so as to cover the entire lower surface of the base region 14.
  • the gate trench portion 40 has a gate trench formed on the upper surface side of the semiconductor substrate 10, a gate insulating film 42, and a gate conductive portion 44.
  • the gate insulating film 42 is formed so as to cover the inner wall of the gate trench.
  • the gate insulating film 42 may be formed by oxidizing or nitriding the semiconductor on the inner wall of the gate trench.
  • the gate conductive portion 44 is formed inside the gate insulating film 42 inside the gate trench. That is, the gate insulating film 42 insulates the gate conductive portion 44 and the semiconductor substrate 10.
  • the gate conductive portion 44 is formed of a conductive material such as polysilicon.
  • the gate conductive portion 44 includes a region facing the base region 14 with the gate insulating film 42 interposed therebetween.
  • the gate trench portion 40 in the cross section is covered with the interlayer insulating film 38 on the upper surface of the semiconductor substrate 10, but the gate conductive portion 44 is connected to the gate electrode in another cross section.
  • a predetermined gate voltage is applied to the gate conductive portion 44, a channel formed by an electron inversion layer is formed in the surface layer of the base region 14 at the interface in contact with the gate trench portion 40.
  • the first donor concentration peak 111 may be provided in the buffer region 20.
  • the second donor concentration peak 121 may be provided in the N-type region above the buffer region 20.
  • the second donor concentration peak 121 may be provided between the buffer region 20 and the storage region 16.
  • the second donor concentration peak 121 of this example is provided in the drift region 18.
  • the second donor concentration peak 121 may be disposed below the lower end of the gate trench portion 40, may be disposed in contact with the lower end of the gate trench portion 40, and may be disposed above the lower end of the gate trench portion 40. It may be arranged.
  • a base doping region 180 which is a region of the substrate base doping concentration Db may be provided between the second donor concentration peak 121 and the accumulation region 16.
  • FIG. 7 is a diagram showing an example of the carrier concentration distribution in the depth direction at the position of line BB in FIG. In FIG. 7, a part of the hydrogen concentration distribution and the helium concentration distribution are shown together.
  • the vertical axis of FIG. 7 is a logarithmic axis.
  • the carrier concentration distribution in the buffer region 20 of this example has a plurality of peaks 24 provided at different positions in the depth direction.
  • Peak 24 is the peak of donor concentration.
  • Peak 24 may have hydrogen as an impurity. Providing the plurality of peaks 24 can further prevent the depletion layer from reaching the collector region 22.
  • the first donor concentration peak 111 may function as the peak 24 in the buffer region 20.
  • the first donor concentration peak 111 may function as a peak farthest from the lower surface 23 of the semiconductor substrate 10 among the plurality of peaks 24 of the buffer region 20.
  • the flat region 150 is arranged between the first donor concentration peak 111 and the second donor concentration peak 121 included in the buffer region 20.
  • the first donor concentration peak 111 may have a higher donor concentration than the peak 24 separated from the lower surface 23 next to the first donor concentration peak 111 among the plurality of peaks 24 of the buffer region 20. By increasing the concentration of the first donor concentration peak 111, the flat region 150 can be easily formed even if the distance between the first donor concentration peak 111 and the second donor concentration peak 121 is large.
  • the hydrogen concentration distribution may have one or more hydrogen concentration peaks 194 between the first depth Z1 and the lower surface 23.
  • the hydrogen concentration peak 194 may be arranged in the buffer region 20 described with reference to FIG.
  • the hydrogen concentration peak 194 may be arranged at the same depth position as the peak 24.
  • the storage area 16 in this example has a plurality of peaks 25.
  • Peak 25 is the peak of donor concentration.
  • the second donor concentration peak 121 is arranged on the lower surface 23 side with respect to the accumulation region 16.
  • a region (base doping region 180) having the base doping concentration Db of the substrate may be provided between the second donor concentration peak 121 and the accumulation region 16.
  • the donor concentration between the second donor concentration peak 121 and the storage region 16 may be higher than the base doping concentration Db of the semiconductor substrate.
  • the base doping concentration Dn of the semiconductor substrate 10 is lower than the base doping concentration Db.
  • the region where the doping concentration is the base doping concentration Dn is the non-doping region 181.
  • the base doping concentration Dn of the non-doping region 181 is, for example, 1 ⁇ 10 10 atoms/cm 3 or more and 5 ⁇ 10 12 atoms/cm 3 or less.
  • the base doping concentration Dn may be 1 ⁇ 10 11 atoms/cm 3 or more.
  • the base doping concentration Dn may be 5 ⁇ 10 12 atoms/cm 3 or less.
  • each concentration in the present specification may be a value at room temperature.
  • the room temperature for example, a value at 300 K (Kelvin) (about 26.9° C.) may be used.
  • FIG. 8 is a diagram showing another structural example of the semiconductor device 100.
  • the semiconductor device 100 of this example is different from the semiconductor device 100 described in FIGS. 6 and 7 in that the second donor concentration peak 121 (and the helium concentration peak 141) is arranged in the accumulation region 16. ..
  • the other structure may be the same as that of the semiconductor device 100 described in FIGS. 6 and 7.
  • FIG. 9 is a diagram showing an example of the carrier concentration distribution in the depth direction at the position of the line CC of FIG. In FIG. 9, a part of the hydrogen concentration distribution and the helium concentration distribution are shown together.
  • the vertical axis of FIG. 9 is a logarithmic axis.
  • the carrier concentration distribution in the storage region 16 of this example has a plurality of peaks provided at different positions in the depth direction.
  • the peak is a peak of donor concentration.
  • the peak in the accumulation region 16 may have hydrogen or phosphorus as an impurity.
  • the second donor concentration peak 121 of this example functions as one of the donor concentration peaks in the accumulation region 16.
  • the second donor concentration peak 121 may function as a peak farthest from the upper surface 21 of the semiconductor substrate 10 among the plurality of peaks of the accumulation region 16.
  • the flat region 150 of this example is arranged between the first donor concentration peak 111 included in the buffer region 20 and the second donor concentration peak 121 included in the accumulation region 16.
  • the donor concentration of the second donor concentration peak 121 may be lower than, the same as, or higher than the donor concentration of the other peak 25 of the buffer region 20.
  • the peak 25 other than the second donor concentration peak 121 may have the same donor concentration.
  • the donor concentration of the second donor concentration peak 121 may be set according to the donor concentration that the flat region 150 should have.
  • the carrier concentration of the drift region 18 of this example may be higher than the base doping concentration Db of the substrate over the entire depth direction. With such a structure, the entire carrier concentration of the drift region 18 can be adjusted accurately.
  • the peak 25 other than the second donor concentration peak 121 may be a peak due to a donor other than hydrogen.
  • peak 25 is a peak in which phosphorus functions as a donor.
  • the width of the second donor concentration peak 121 in the depth direction may be wider than the width of the peak 25 in the depth direction. Thereby, the displacement current to the gate trench portion can be further suppressed.
  • a valley of the donor concentration distribution may be present between the second donor concentration peak 121 and the peak 25 of the accumulation region 16 as shown in FIG.
  • the donor concentration distribution in the accumulation region 16 may be a kink instead of a valley.
  • FIG. 10 shows the hydrogen concentration distribution, the helium concentration distribution, and the carrier concentration distribution in the depth direction at the position shown by the line AA in FIG.
  • the carrier concentration was measured by SR method. More defects are more likely to occur in the vicinity of the range (Z2) of the helium concentration peak 141 than in the passage region 106. The defect remaining without being bonded to hydrogen may cause a valley 151 in the carrier concentration distribution in the vicinity of the second depth Z2.
  • the slope of the upward slope 122 of the second donor concentration peak 121 may be steep in calculation. Therefore, it is preferable to calculate the slope of the uphill slope 122 by excluding the influence of the valley 151.
  • the slopes of the upward slopes of the second donor concentration peak 121 and the helium concentration peak 141 may be calculated using the concentrations at the second depth Z2 and the concentrations at the depth Zc.
  • the depth Zc may be a position closer to the lower surface 23 than the valley 151.
  • the depth Zc is the central depth of the flat region 150 in the depth direction.
  • the standardization may use the gradient of the density difference or the gradient of the density ratio.
  • FIG. 11 is a diagram showing an arrangement example of each element on the upper surface 21 of the semiconductor substrate 10.
  • the outer peripheral edge of the semiconductor substrate 10 is defined as the outer peripheral edge 140.
  • the semiconductor device 100 includes an active section 120 and an edge termination structure section 90.
  • the active portion 120 is a region in which a main current flows between the upper surface 21 and the lower surface 23 of the semiconductor substrate 10 when the semiconductor device 100 is controlled to be in the ON state. That is, it is a region in the semiconductor substrate 10 where current flows in the depth direction from the upper surface 21 to the lower surface 23 or from the lower surface 23 to the upper surface 21.
  • the active section 120 of this example is provided with a transistor section 70 and a diode section 80.
  • the transistor unit 70 and the diode unit 80 may be arranged side by side in the X-axis direction. In the example of FIG. 11, the transistor section 70 and the diode section 80 are arranged alternately in contact with each other in the X-axis direction.
  • the transistor section 70 may be provided at both ends of the active section 120 in the X-axis direction.
  • the emitter electrode 52 may cover the transistor section 70 and the diode section 80.
  • the active part 120 may refer to a region covered with the emitter electrode 52.
  • the transistor unit 70 of this example has the IGBT (gate insulation type bipolar transistor) described in FIGS. 6 to 10.
  • the diode unit 80 of this example has an FWD (free wheeling diode).
  • an N+ type cathode region 82 is provided in a region in contact with the lower surface 23 of the semiconductor substrate 10.
  • the diode portion 80 shown by the solid line is a region where the cathode region 82 is provided on the lower surface 23 of the semiconductor substrate 10.
  • the collector region 22 is provided in a region other than the cathode region 82 in the region in contact with the lower surface 23 of the semiconductor substrate 10.
  • the diode part 80 is a region obtained by projecting the cathode region 82 in the Z-axis direction.
  • the transistor part 70 is a region in which the collector region 22 is provided on the lower surface 23 of the semiconductor substrate 10 and the unit structure including the emitter region 12 is periodically provided on the upper surface 21 of the semiconductor substrate 10.
  • the boundary between the diode portion 80 and the transistor portion 70 in the Y-axis direction is the boundary between the cathode region 82 and the collector region 22.
  • a portion of the projected region of the cathode region 82 extending to the end of the active portion 120 or the gate runner 48 in the Y-axis direction (the portion shown by the broken line of the extended diode portion 80 in FIG. 11) is also included in the diode portion 80. May be included.
  • the extension region is not provided with the emitter region 12.
  • the semiconductor device 100 of this example further includes a gate metal layer 50 and a gate runner 48. Further, the semiconductor device 100 may have each pad such as the gate pad 116 and the emitter pad 118.
  • the gate pad 116 is electrically connected to the gate metal layer 50 and the gate runner 48.
  • the emitter pad 118 is electrically connected to the emitter electrode 52.
  • the gate metal layer 50 may be provided so as to surround the active portion 120 in a top view.
  • the gate pad 116 and the emitter pad 118 may be located in the region surrounded by the gate metal layer 50.
  • the gate metal layer 50 may be formed of a metal material such as aluminum or an aluminum silicon alloy.
  • the gate metal layer 50 is insulated from the semiconductor substrate 10 by the interlayer insulating film 38. In FIG. 11, the interlayer insulating film 38 is omitted.
  • the gate metal layer 50 is provided separately from the emitter electrode 52.
  • the gate metal layer 50 transfers the gate voltage applied to the gate pad 116 to the transistor unit 70.
  • the gate conductive portion 44 of the transistor portion 70 is directly connected to the gate metal layer 50 or indirectly connected via another conductive member.
  • the gate runner 48 connects the gate metal layer 50 and the gate conductive portion 44.
  • the gate runner 48 may be formed of a semiconductor material such as polysilicon doped with impurities.
  • a part of the gate runner 48 may be provided above the active portion 120.
  • the gate runner 48 shown in FIG. 11 is provided across the active portion 120 in the X-axis direction. As a result, it is possible to suppress the decrease and delay of the gate voltage even inside the active portion 120, which is separated from the gate metal layer 50.
  • a part of the gate runner 48 may be disposed along the gate metal layer 50 so as to surround the active portion 120.
  • the gate runner 48 may be connected to the gate conductive portion 44 at the end of the active portion 120.
  • the edge termination structure portion 90 is provided on the upper surface 21 of the semiconductor substrate 10 between the active portion 120 and the outer peripheral end 140 of the semiconductor substrate 10.
  • the gate metal layer 50 is arranged between the edge termination structure portion 90 and the active portion 120.
  • the edge termination structure portion 90 may be annularly arranged on the upper surface 21 of the semiconductor substrate 10 so as to surround the active portion 120.
  • the edge termination structure 90 of this example is arranged along the outer peripheral edge 140 of the semiconductor substrate 10.
  • the edge termination structure portion 90 relaxes electric field concentration on the upper surface 21 side of the semiconductor substrate 10.
  • the edge termination structure 90 has, for example, a guard ring, a field plate, a RESURF, and a structure combining these.
  • FIG. 12 is a diagram showing an example of a cc′ cross section in FIG. 11.
  • FIG. 12 shows an arrangement example of the passage area 106 described in FIGS. 1 to 10 in the cross section.
  • the passage area 106 is hatched. Note that FIG. 12 shows only the passage region 106 in the drift region 18, and omits the passage regions 106 in the buffer region 20, the collector region 22, and the cathode region 82.
  • the cross section shown in FIG. 12 is an XZ plane including the edge termination structure portion 90, the transistor portion 70, and the diode portion 80. Although the gate metal layer 50 and the gate runner 48 are disposed between the edge termination structure portion 90 and the transistor portion 70, they are omitted in FIG.
  • the structure of the transistor unit 70 is similar to that of the IGBT described in FIGS. 6 to 10.
  • the diode portion 80 includes the base region 14, the drift region 18, the cathode region 82, and the dummy trench portion 30 inside the semiconductor substrate 10.
  • the base region 14 and the drift region 18 are the same as the base region 14 and the drift region 18 in the transistor section 70.
  • the base region 14 may be provided in a region of the diode portion 80 that is in contact with the upper surface 21 of the semiconductor substrate 10, and the contact region 15 may be provided.
  • the contact region 15 is a P+ type region having a higher doping concentration than the base region 14.
  • the diode region 80 of this example is not provided with the emitter region 12. Further, the diode portion 80 may or may not be provided with the storage region 16.
  • the dummy trench section 30 has the same structure as the gate trench section 40. However, the dummy trench portion 30 is electrically connected to the emitter electrode 52. The dummy trench portion 30 is provided from the upper surface 21 of the semiconductor substrate 10 to the drift region 18 through the base region 14. The dummy trench section 30 may also be provided in the transistor section 70. The dummy trench portion 30 and the gate trench portion 40 may be arranged in the transistor portion 70 at a predetermined cycle.
  • the intermediate boundary region 190 is a region in which neither the operation of the transistor unit 70 nor the operation of the diode unit 80 is directly performed.
  • the region in contact with the upper surface 21 of the intermediate boundary region 190 may have the same structure as the upper surface 21 side of the diode unit 80.
  • the collector region of the transistor unit 70 may be provided so as to extend in a region in contact with the lower surface 23 of the intermediate boundary region 190 in a top view.
  • only the range example of the intermediate boundary region 190 is indicated by an arrow.
  • the range illustrated as the intermediate boundary region 190 has the same structure as the transistor unit 70.
  • the lifetime control region 192 may be provided on the upper surface 21 side with respect to the center in the depth direction.
  • the lifetime control region 192 is a region in which the recombination center of carriers (electrons or holes) is provided at a higher concentration than the periphery.
  • the recombination center may be a vacancy-based defect such as a vacancy or a double vacancy, a dislocation, an interstitial atom, or a transition metal.
  • the lifetime control region 192 may extend from the diode portion 80 to the intermediate boundary region 190.
  • the edge termination structure 90 is provided with a plurality of guard rings 92, a plurality of field plates 94 and a channel stopper 174.
  • the collector region 22 may be provided in a region in contact with the lower surface 23.
  • Each guard ring 92 may be provided on the upper surface 21 so as to surround the active portion 120.
  • the plurality of guard rings 92 may have a function of spreading the depletion layer generated in the active portion 120 to the outside of the semiconductor substrate 10. Thereby, the electric field concentration inside the semiconductor substrate 10 can be prevented, and the breakdown voltage of the semiconductor device 100 can be improved.
  • the guard ring 92 of this example is a P+ type semiconductor region formed by ion implantation near the upper surface 21.
  • the bottom of the guard ring 92 may be deeper than the bottoms of the gate trench portion 40 and the dummy trench portion 30.
  • the upper surface of the guard ring 92 is covered with the interlayer insulating film 38.
  • the field plate 94 is formed of a conductive material such as metal or polysilicon.
  • the field plate 94 may be formed of the same material as the gate metal layer 50 or the emitter electrode 52.
  • the field plate 94 is provided on the interlayer insulating film 38.
  • the field plate 94 is connected to the guard ring 92 through a through hole provided in the interlayer insulating film 38.
  • a protective film 182 is provided on the upper surface 21 side of the semiconductor substrate 10.
  • the protective film 182 may cover the edge termination structure portion 90, the gate metal layer 50, the boundary portion 72, and a part of a portion in contact with the boundary portion 72 among the active portions.
  • the protective film 182 may be an insulating film or an organic thin film.
  • the protective film 182 of this example is polyimide.
  • the plating layer 184 may be provided on the entire surface of the exposed portion of the emitter electrode 52 where the protective film 182 is not formed. The surface of the plating layer 184 may be located closer to the upper surface 21 side than the surface of the protective film 182.
  • the plating layer 184 is connected to the electrode terminals of the power module on which the semiconductor device 100 is mounted.
  • the channel stopper 174 is provided so as to be exposed on the upper surface 21 and the side surface at the outer peripheral end 140.
  • the channel stopper 174 is an N-type region having a higher doping concentration than the drift region 18.
  • the channel stopper 174 has a function of terminating the depletion layer generated in the active portion 120 at the outer peripheral edge 140 of the semiconductor substrate 10.
  • a boundary portion 72 may be provided between the transistor portion 70 and the edge termination structure portion 90.
  • the boundary portion 72 may have the contact region 15, the base region 14, and the dummy trench portion 30 on the upper surface 21 side of the semiconductor substrate 10.
  • the boundary portion 72 may include the P+ type well region 11 having a higher doping concentration than the base region 14.
  • the well region 11 is provided in contact with the upper surface 21 of the semiconductor substrate 10.
  • a gate metal layer 50 and a gate runner 48 may be provided above the well region 11.
  • the bottom of the well region 11 may have the same depth as the bottom of the guard ring 92.
  • a part of the trench portion in the boundary portion 72 may be formed in the well region 11.
  • the collector region 22 may be provided in a region of the boundary portion 72 in contact with the lower surface 23.
  • the helium concentration peak 141 is arranged between the bottom portion of the gate trench portion 40 in the Z-axis direction and the upper surface 21 of the semiconductor substrate 10.
  • the helium concentration peak 141 is arranged at a position deeper than the accumulation region 16, but the helium concentration peak 141 may be arranged at the same depth as the accumulation region 16, and the helium concentration peak 141 and the base region 14 may be arranged. It may be arranged at the same depth, or may be arranged at the same depth as the emitter region 12.
  • the storage region 16 may also be formed in the diode portion 80 as shown by the dotted line in FIG.
  • the passage region 106 is formed in the range from the lower surface 23 of the semiconductor substrate 10 to the helium concentration peak 141. In each figure, the helium concentration peak 141 and the passage region 106 do not overlap each other, but the passage region 106 is formed up to the depth of the helium concentration peak 141.
  • the passage region 106 of this example is provided in each of the transistor section 70, the diode section 80, the boundary section 72, and the edge termination structure section 90.
  • the depth of the passage region 106 may be the same.
  • the passage region 106 may be provided in the entire top view of the semiconductor substrate 10. According to this example, the donor concentration can be adjusted over almost the entire depth of the semiconductor substrate 10. Further, the donor concentration can be adjusted over almost the entire top surface of the semiconductor substrate 10.
  • a region where the passage region 106 is not formed is provided particularly in a portion in contact with the upper surface 21 of the edge termination structure portion 90.
  • the region where the passage region 106 is not formed is a portion where the donor concentration becomes the same as the base doping concentration Db.
  • a region where the passage region 106 is not formed is on the upper surface 21 side with respect to the depth of the helium concentration peak 141. That is, the region where the passage region 106 is not formed may be a region where the doping concentration is almost the base doping concentration Db.
  • the region where the doping concentration is the base doping concentration Db is referred to as the base doping region 180.
  • the base doping region 180 is provided in contact with the upper surface 21 and in a portion shallower than the well region 11.
  • FIG. 13 is a diagram showing another arrangement example of the passage area 106.
  • the passage area 106 of this example is different from the passage area 106 in FIG. 12 in width in the depth direction.
  • the arrangement in a top view is the same as the passage area 106 in FIG.
  • the helium concentration peak 141 of this example is arranged between the bottom of the gate trench 40 and the lower surface 23 of the semiconductor substrate 10.
  • the thickness of the semiconductor substrate 10 in the depth direction is T1
  • the distance between the helium concentration peak 141 and the lower surface 23 of the semiconductor substrate 10 is T2.
  • the distance T2 corresponds to the thickness of the passage area 106 in the depth direction.
  • the distance T2 may be 40% or more and 60% or less of the thickness T1. That is, the passage region 106 may be provided from the lower surface 23 of the semiconductor substrate 10 to almost the center in the depth direction of the semiconductor substrate 10. However, the distance T2 can be changed as appropriate.
  • the base doping region 180 is provided on the upper surface 21 side of the helium concentration peak 141.
  • the base doping region 180 of this example is a region from the bottom surface of the trench portion to the helium concentration peak 141, and has a depth of about T1-T2.
  • the base doping region 180 of this example is provided on the entire surface of the semiconductor substrate 10.
  • FIG. 14 is a diagram showing another arrangement example of the passage area 106.
  • the passage area 106 of the present example is different from the passage area 106 in FIG. 12 in the arrangement in top view.
  • the arrangement in the depth direction may be the same as the passage area 106 in FIG.
  • the passage region 106 and the helium concentration peak 141 are not provided in at least a partial region of the edge termination structure portion 90 in a top view.
  • FIG. 14 shows an example in which the passage region 106 and the helium concentration peak 141 are not provided in the entire edge termination structure portion 90 in a top view.
  • the passage region 106 and the helium concentration peak 141 may be provided at the end portion of the edge termination structure portion 90 near the active portion 120. That is, the passage region 106 and the helium concentration peak 141 are not provided in the region in contact with the outer peripheral edge 140 of the semiconductor substrate 10.
  • the helium concentration peak 141 is not provided near the outer peripheral edge 140, it is possible to suppress the formation of defects near the outer peripheral edge 140. Therefore, it is possible to suppress an increase in leakage at the outer peripheral edge 140.
  • the base doping region 180 of this example is provided in a region in contact with the outer peripheral edge 140 of the semiconductor substrate 10.
  • the base doping region 180 of this example is provided in at least a part of the region of the edge termination structure 90 in a top view. Further, the base doping region 180 may be provided on the entire edge termination structure 90 and the boundary 72 in a top view.
  • the arrangement of the passage region 106 of the boundary portion 72 may be the same as that of the edge termination structure portion 90, that of the transistor portion 70, or that of the diode portion 80.
  • FIG. 14 shows an example in which the passage area 106 is not provided in the boundary portion 72.
  • FIG. 15 is a diagram showing another arrangement example of the passage area 106.
  • the passage area 106 of the present example has the same arrangement in the depth direction as the passage area 106 shown in FIG. 13, and the arrangement in top view is the same as the passage area 106 shown in FIG. 14. That is, the passage region 106 is not provided in the edge termination structure portion 90. Further, the transistor portion 70 and the diode portion 80 are provided with a passage region 106 from the lower surface 23 of the semiconductor substrate 10 to the vicinity of the center in the depth direction of the semiconductor substrate 10.
  • the base doping region 180 of this example is formed from the upper surface 21 to the buffer region 20 at the boundary 72 and the edge termination structure 90. Further, in the active portion, the base doping region 180 is formed in the drift region 18 on the upper surface 21 side of the helium concentration peak 141. On the upper surface 21 side of the helium concentration peak 141, the base doping region 180 of this example is provided on the entire surface of the semiconductor substrate 10 in a top view.
  • FIG. 16A is a diagram showing another arrangement example of the passage area 106. This example is different from the examples in FIGS. 12 to 15 in that the passing region 106 and the helium concentration peak 141 are not provided in at least a part of the diode portion 80 in a top view.
  • the other structure is the same as the example described in FIGS.
  • FIG. 16A shows an example in which the passing region 106 and the helium concentration peak 141 are not provided in the entire diode portion 80 in a top view. That is, the base doping region 180 is provided on the entire diode portion 80 in a top view. Further, the base doping region 180 is also provided on the entire boundary portion 72 and the edge termination structure portion 90. In another example, the passage region 106 and the helium concentration peak 141 may be provided at the end portion of the diode portion 80 that is in contact with the transistor portion 70. By making the arrangement of the passage region 106 different between the transistor section 70 and the diode section 80, the distributions of the doping concentrations of the diode section 80 and the transistor section 70 can be made different as appropriate.
  • FIG. 16B is a diagram showing another arrangement example of the passage area 106.
  • 16B shows a configuration in which the pass-through region 106 and the base doping region 180 are formed in the active portion in the opposite manner to FIG. 16A.
  • the passage region 106 in the diode portion 80, the expansion of the space charge region at the time of reverse recovery is suppressed and the waveform vibration at the time of reverse recovery is suppressed.
  • the transistor part 70 as the base doping region 180, for example, when a short circuit occurs, expansion of the space charge region is promoted, injection of holes is promoted, and short circuit breakdown is suppressed.
  • FIG. 17A is a diagram showing another arrangement example of the passage area 106.
  • the passage area 106 in this example has the same arrangement in the depth direction as the passage area 106 shown in FIG. 13, and the arrangement in a top view is the same as the passage area 106 shown in FIG. 16A. That is, the diode region 80 is not provided with the passage region 106.
  • a passage region 106 is provided from the lower surface 23 of the semiconductor substrate 10 to the vicinity of the center of the semiconductor substrate 10 in the depth direction. Further, in the example of FIG.
  • the helium concentration peak 141 is made to recede from the bottom surface of the trench portion to the lower surface 23 side, and the base doping region 180 is formed on the entire upper surface side on the upper surface 21 side with respect to the helium concentration peak 141.
  • FIG. 17B is a diagram showing another arrangement example of the passage area 106.
  • the example of FIG. 17B has a configuration in which the passage region 106 and the base doping region 180 are formed in the active portion in the opposite manner to that of FIG. 17A. Also in the example of FIG. 17B, the same effect as that of FIG. 16B is obtained.
  • helium ions are selectively implanted in a top view in a second implantation step S1902 described later.
  • selective helium ion implantation can be performed using the photoresist film 200 shown in FIGS. 14 to 17B.
  • a photoresist film 200 having a predetermined thickness is selectively formed on a part of the lower surface 23 of the semiconductor substrate 10.
  • the thickness of the photoresist film 200 is a thickness that can shield helium ions.
  • a second implantation step S1902 is performed.
  • Helium ions are shielded by the photoresist film 200 in the region where the photoresist film 200 is formed. Therefore, helium ions do not enter the region of the semiconductor substrate 10 covered with the photoresist film 200.
  • Helium ions are implanted into the second depth position Z2 in the region where the photoresist film 200 is not formed, depending on the acceleration energy.
  • the photoresist film 200 is formed in contact with the lower surface 23 of the semiconductor substrate 10.
  • the collector electrode 54 is not provided on the lower surface 23.
  • FIG. 17C is a diagram for explaining the minimum film thickness M of the photoresist film 200 for preventing helium ions from entering the semiconductor substrate 10.
  • FIG. 17C shows the film thickness M with respect to the range Rp of helium ions.
  • the helium ions of this example may be injected from the accelerator into the semiconductor substrate 10 without passing through an absorber other than the photoresist film 200.
  • the range Rp of helium ions is uniquely determined by the acceleration energy in the accelerator.
  • the minimum film thickness M of the photoresist film 200 that can shield helium ions is determined by the acceleration energy of helium ions. Therefore, the minimum thickness M of the photoresist film 200 can be represented by the range Rp of helium ions.
  • FIG. 17C is a diagram in which the relationship between the range Rp of helium ions and the film thickness M is measured at three points and is approximated by a straight line.
  • the thickness of the photoresist film 200 is preferably equal to or larger than the minimum film thickness M shown by the above equation.
  • helium ions may be injected into the semiconductor substrate 10 from the accelerator via an absorber other than the photoresist film 200.
  • the range Rp of helium ions is determined by the acceleration energy in the accelerator and the thickness of the absorber along the implantation direction of helium ions.
  • FIG. 18A is a diagram showing another arrangement example of the passage area 106.
  • the width T5 in the depth direction of the passage region 106 provided in the edge termination structure portion 90 is the width T4 in the depth direction of the passage region 106 provided in the active portion 120 (the diode portion 80 in this example). Shorter than.
  • the helium concentration peak 141 may be arranged between the bottom of the dummy trench section 30 and the upper surface 21 of the semiconductor substrate 10. In the edge termination structure portion 90, the helium concentration peak 141 may be arranged between the guard ring 92 and the lower surface 23 of the semiconductor substrate 10.
  • the width T5 of the passage region 106 in the edge termination structure 90 may be larger than half the thickness T of the semiconductor substrate 10.
  • the width T3 of the passage region 106 provided in the transistor portion 70 in the depth direction may be shorter than the width T4 of the passage region 106 provided in the diode portion 80 in the depth direction. That is, in the transistor part 70, the base doping region 180 is formed deeper than the depth of the trench part. That is, the helium concentration peak 141 of the transistor part 70 is located closer to the lower surface 23 side than the bottom surface of the trench part. In the transistor part 70, the helium concentration peak 141 may be arranged between the bottom part of the gate trench part 40 and the lower surface 23 of the semiconductor substrate 10.
  • the width T3 may be the same as the width T5, may be larger than the width T5, or may be smaller than the width T5.
  • the width T3 of the passage region 106 in the transistor portion 70 may be larger than half the thickness T of the semiconductor substrate 10.
  • the pass region 106 at the boundary portion 72 may have the same structure as the pass region 106 in the edge termination structure portion 90, may have the same structure as the pass region 106 in the transistor portion 70, and may have the pass portion in the diode portion 80. It may have the same structure as the region 106. Further, in the example of FIG. 18A, the passage region 106 may not be provided in the transistor unit 70. The passing region 106 may not be provided in the diode portion 80. The passage region 106 may not be provided in the edge termination structure portion 90. The passage area 106 may not be provided in the boundary portion 72.
  • FIG. 18B is a diagram showing another arrangement example of the passage area 106.
  • the width T5 in the depth direction of the passage region 106 provided in the edge termination structure portion 90 is the width T3 in the depth direction of the passage region 106 provided in the active portion 120 (transistor portion 70 in this example). Shorter than.
  • the helium concentration peak 141 may be arranged between the bottom of the gate trench section 40 and the upper surface 21 of the semiconductor substrate 10.
  • the structures of the passage region 106 and the helium concentration peak 141 in the edge termination structure portion 90 are similar to those in the example of FIG. 18A.
  • the width T4 in the depth direction of the passage region 106 provided in the diode portion 80 may be shorter than the width T3 in the depth direction of the passage region 106 provided in the transistor portion 70. That is, in the diode portion 80, the base doping region 180 is formed deeper than the trench portion depth. That is, the helium concentration peak 141 of the diode portion 80 is located closer to the lower surface 23 side than the bottom surface of the trench portion. In the diode section 80, the helium concentration peak 141 may be arranged between the bottom of the dummy trench section 30 and the lower surface 23 of the semiconductor substrate 10.
  • the width T4 may be the same as the width T5, larger than the width T5, or smaller than the width T5.
  • the width T4 of the passage region 106 in the diode portion 80 may be larger than half the thickness T of the semiconductor substrate 10.
  • the pass region 106 at the boundary portion 72 may have the same structure as the pass region 106 in the edge termination structure portion 90, may have the same structure as the pass region 106 in the transistor portion 70, and may have the pass portion in the diode portion 80. It may have the same structure as the region 106. Further, in the example of FIG. 18B, the passage region 106 may not be provided in the transistor unit 70. The passing region 106 may not be provided in the diode portion 80. The passage region 106 may not be provided in the edge termination structure portion 90. The passage area 106 may not be provided in the boundary portion 72.
  • the donor concentration distribution in the transistor section 70, the diode section 80, and the edge termination structure section 90 can be easily adjusted by adjusting the structure of the passage region 106.
  • the structure of the passage area 106 is not limited to the examples shown in FIGS. 12 to 18B.
  • FIG. 19 is a diagram showing a step of forming the passage region 106 in the method of manufacturing the semiconductor device 100.
  • hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 to the first depth Z1 in the first implantation step S1900.
  • the passage region 106 is formed by implanting helium ions from the lower surface 23 of the semiconductor substrate 10 to the second depth Z2. Either the first injection step S1900 or the second injection step S1902 may be performed first.
  • the donor concentration in the passage region 106 may not be increased. That is, if the heat treatment is performed before forming the passage region 106, the hydrogen implanted in the first implantation step S1900 may not be combined with the crystal defects in the passage region 106 and may escape to the outside of the semiconductor substrate 10. Therefore, it is preferable that the heat treatment is not performed between the first implantation step S1900 and the second implantation step S1902.
  • the heat treatment is, for example, a treatment of heating the semiconductor substrate 10 at 300° C. or higher.
  • a diffusion step S1904 is performed after the first injection step S1900 and the second injection step S1902.
  • the semiconductor substrate 10 is heat-treated to diffuse the hydrogen implanted into the first depth Z1 into the passage region 106.
  • the semiconductor substrate 10 may be heated to 300° C. or higher. The heating temperature may be 350° C. or higher.
  • the semiconductor substrate 10 may be heated for 1 hour or longer, or may be heated for 3 hours or longer.
  • the crystal defects in the passage region 106 and hydrogen are combined to form a donor.
  • the donor concentration in the passage region 106 can be increased.
  • the minimum donor concentration of the passage region 106 is preferably higher than the donor concentration (base doping concentration) of the semiconductor substrate 10 before the first implantation step S1900 and the second implantation step S1902. That is, it is preferable that the donor concentration be higher than the base doping concentration in the entire passage region 106.
  • the hydrogen injected at the first depth position Z1 diffuses to the vicinity of the second depth position Z2.
  • the dose amount of hydrogen is preferably determined so that the minimum value of the donor concentration in the passage region 106 is higher than the base doping concentration.
  • hydrogen ions may be implanted near the helium ion stop region (range Rp).
  • the hydrogen ion implantation in the first implantation step may be performed before or after the helium ion implantation in the second implantation step S1902.
  • Ion implantation damage (disorder) is also localized near the helium ion stop region. There are many dangling bonds in disorder.
  • hydrogen ions are also implanted in the vicinity of the helium ion stop region, whereby hydrogen terminates disordered dangling bonds, and disorder can be reduced.
  • hydrogen ion implantation may be performed multiple times in addition to the hydrogen ion implantation in the first implantation step S1900.
  • the plurality of hydrogen ion implantations for forming the peak 24 may be performed in the first implantation step S1900. That is, the first injection step S1900 may be performed multiple times.
  • FIGS. 20 to 26 are diagrams for explaining a method of determining the dose amount of hydrogen ions to be implanted at the first depth Z1 (referred to as a first dose amount).
  • a first dose amount it is determined from the diffusion coefficient of hydrogen in the semiconductor substrate 10 and the position of the second depth Z2 (that is, the distance at which the hydrogen implanted at the first depth position Z1 should diffuse). Hydrogen is implanted at a dose amount equal to or higher than the minimum dose amount.
  • FIG. 20 is a diagram showing an example of carrier concentration distribution in the semiconductor substrate 10 after the diffusion step S1904.
  • the carrier concentration distribution of FIG. 20 can be acquired by, for example, spread resistance measurement (Spread Resistance Profiling).
  • the lower surface 23 of the semiconductor substrate 10 is set as a reference position (0 ⁇ m) of depth ( ⁇ m).
  • the first depth Z1 is 10 ⁇ m or less.
  • the first depth Z1 may be treated as 0 ⁇ m.
  • the first example 161, the second example 162, and the third example 163 are examples in which hydrogen ions are implanted into the first depth Z1 and helium ions are implanted into the second depth Z2.
  • the fourth example 164 and the fifth example 165 are examples in which helium ions are implanted into the second depth Z2 and hydrogen is not implanted into the first depth Z1.
  • the dose amount of helium ions to the second depth Z2 (referred to as the second dose amount) was set to 1 ⁇ 10 13 /cm 2 .
  • the range of helium ions to the second depth Z2 was 100 ⁇ m
  • the acceleration energy was 4.0 Mev.
  • the range of helium ions may be adjusted by acceleration energy, or may be adjusted by an aluminum absorber or the like.
  • the acceleration energy of hydrogen ions to the first depth Z1 was 400 keV.
  • the first dose amount was set to 1 ⁇ 10 15 /cm 2 .
  • the first dose amount was 3 ⁇ 10 14 /cm 2 .
  • the first dose amount was set to 1 ⁇ 10 14 /cm 2 .
  • FIG. 20 is a carrier concentration distribution after annealing.
  • crystal defects are formed in the passage region 106 (the range from the lower surface 23 of the semiconductor substrate 10 to the second depth position Z2). Therefore, the carrier concentration in the passage region 106 is reduced.
  • the first dose amount is Q
  • the diffusion depth of hydrogen from the first depth Z1 is x(x1, x2, x3) (cm)
  • the diffusion coefficient of hydrogen is D (cm 2 /s)
  • the diffusion time is
  • t is the base doping concentration of the semiconductor substrate 10 and C 0 (atoms/cm 3 )
  • Expression (1) is a value calculated from the solution of the diffusion equation.
  • the diffusion equation is solved under the boundary condition that the total amount of hydrogen is constant, the solution has a Gaussian distribution.
  • x when the concentration C(x, t) matches the base doping concentration C 0 is the equation (1).
  • the hydrogen diffusion coefficient D in the first example 161, the second example 162, and the third example 163 can be calculated numerically from the equation (1).
  • the diffusion depth x in each example may be determined from the profile shape of FIG. For example, as the diffusion depth x, the distance from the first depth position Z1 to the first inflection point in the valley portion of the carrier concentration can be used. As the diffusion depth x, the distance from the first depth position Z1 to the position where the carrier concentration first falls below the base doping concentration may be used.
  • the crystal defects formed when hydrogen ions are implanted to the second depth Z2 are various defects such as point defects and dislocations.
  • the point defects vacancies and compound vacancies, in particular, are formed.
  • the concentration of crystal defects has a peak at a position slightly closer to the ion implantation surface (the lower surface 23 of the semiconductor substrate 10) from the second depth Z2.
  • FIG. 21 is a diagram showing the relationship between the hydrogen diffusion coefficient D and the first dose amount Q.
  • the first example 161, the second example 162, and the third example 163 shown in FIG. 20 are plotted.
  • the diffusion coefficient D increases.
  • the hydrogen injected into the first depth Z1 diffuses toward the second depth Z2 while terminating the dangling bond in the passage region 106.
  • the proportion of hydrogen diffusing in the region where the dangling bonds are terminated increases, and it is considered that hydrogen easily diffuses.
  • the value of the diffusion coefficient D varies depending on experimental conditions and the like. An error of at least ⁇ 50% is acceptable with respect to the diffusion coefficient D shown in FIG. Errors within ⁇ 100% are also acceptable.
  • FIG. 22 is a diagram showing the relationship between the diffusion coefficient D and the annealing temperature T.
  • FIG. 22 is a graph obtained by acquiring the diffusion coefficient described in FIGS. 20 and 21 for a plurality of annealing temperatures T and performing Arrhenius plotting.
  • D 0 is a constant
  • Ea is an activation energy
  • FIG. 23 is a diagram showing the relationship between the hydrogen diffusion depth and the first dose amount.
  • the first example 161, the second example 162, and the third example 163 shown in FIG. 20 are plotted with black circles.
  • the first dose amount with respect to each diffusion depth x can be determined. That is, the straight line indicates the minimum first dose amount for each diffusion depth x.
  • the donor concentration of the entire passing region 106 can be made higher than the base doping concentration.
  • the first dose amount Q (ions/cm 2 ) may satisfy the following equation when the second depth Z2 is the diffusion depth x ( ⁇ m). Q ⁇ 1.6491 ⁇ 10 13 ⁇ e 0.061619x
  • the peak of the crystal defect concentration when helium ions are implanted to the second depth Z2 is provided at a position slightly shallower than the second depth Z2.
  • the horizontal axis of FIG. 23 corresponds to the peak position of the crystal defect concentration. Therefore, when forming the passage region 106 having the length X0 corresponding to the horizontal axis of FIG. 23, the straggling ⁇ Rp in the ion implantation is taken into consideration, and the range Rp of the following formula is used to obtain the second depth Z2. Implant helium ions into.
  • the passage region 106 can be formed in almost the entire depth direction.
  • the minimum dose amount may be calculated based on the following equation (2) obtained by modifying the equation (1).
  • the diffusion coefficient D is calculated by the method described in FIG. In FIG. 23, the minimum dose amount calculated from the equation (2) is plotted by a white circle. Since the diffusion coefficient D has a dimension of the square of the distance, the diffusion coefficient D may be expressed as a function of the hydrogen diffusion depth x.
  • FIG. 24 is a diagram showing the relationship between the diffusion coefficient D and the diffusion depth x.
  • the first example 161, the second example 162, and the third example 163 in FIG. 20 are plotted.
  • the diffusion coefficient D increases.
  • the diffusion depth x increases, the distance from the first depth Z1 to the concentration peak of crystal defects increases. For this reason, the proportion of the region having relatively few crystal defects in the passage region 106 increases. Since the diffusion coefficient increases when the number of crystal defects is small, the average diffusion coefficient of the passage region 106 also increases when the diffusion depth x increases.
  • the second dose amount is set to 1 ⁇ 10 13 /cm 2 .
  • the minimum dose amount of the first dose amount can be determined by the same method.
  • the donor concentration in the passage region 106 may be adjusted by adjusting the second dose amount.
  • the concentration of crystal defects formed in the passage region 106 can be adjusted.
  • the annealing temperature is set to 370° C., the minimum dose amount can be determined from the equation (2) even if the annealing temperature is changed.
  • FIG. 25 is a diagram showing straight lines defining the minimum dose amount for each annealing temperature.
  • the diffusion coefficient D is constant regardless of the diffusion depth.
  • hydrogen ions may be implanted at the first depth Z1 with a dose amount larger than the minimum dose amount shown by the straight line in FIG.
  • FIG. 26 is a diagram showing the relationship between the second dose amount and the minimum dose amount of the first dose amount. In this example, the relationship is shown for each diffusion depth x.
  • hydrogen ions may be implanted to the first depth Z1 with a dose amount larger than the minimum dose amount shown by the straight line in FIG.
  • FIG. 27 is a diagram illustrating an example of the first depth Z1. 27, the donor concentration distribution, the hydrogen chemical concentration distribution, and the helium chemical concentration distribution in the depth direction of the semiconductor substrate 10 are shown.
  • the hydrogen chemical concentration distribution and the helium chemical concentration distribution schematically show only the vicinity of the peak.
  • the distribution in the vicinity of the upper surface 21 of the semiconductor substrate 10 (a region where the distance from the lower surface 23 is 100 ⁇ m or more) is omitted.
  • the carrier concentration distribution in the N-type region of the semiconductor substrate 10 may be used as the donor concentration distribution.
  • the first depth Z1 of the hydrogen concentration peak 131 is included in the range of 5 ⁇ m or less in the depth direction from the lower surface 23 of the semiconductor substrate 10.
  • the configuration other than the first depth Z1 is the same as any one of the modes described in FIGS. 1 to 26.
  • the donor concentration distribution of the semiconductor device 100 of this example is similar to that of the example of FIG.
  • the first depth Z1 may be included in the range of 4 ⁇ m or less from the lower surface 23, and may be included in the range of 3 ⁇ m or less.
  • the dose amount of hydrogen injected into the first depth Z1 of hydrogen may be 1 ⁇ 10 15 atoms/cm 2 or more, 1 ⁇ 10 16 atoms/cm 2 or more, and 1 ⁇ . It may be 10 17 atoms/cm 2 or more, or 1 ⁇ 10 18 atoms/cm 2 or more.
  • a first donor concentration peak 111 due to a hydrogen donor may be formed at the first depth Z1.
  • the donor concentration of the first donor concentration peak 111 may be 1 ⁇ 10 15 /cm 3 or higher, or 1 ⁇ 10 16 /cm 3 or higher.
  • the donor concentration of the first donor concentration peak 111 may be 1 ⁇ 10 17 /cm 3 or less.
  • the implantation of hydrogen to the first depth Z1 may be performed by plasma doping.
  • a gas for plasma excitation and a raw material gas containing hydrogen are supplied into a container for housing the semiconductor substrate 10.
  • the excitation gas may include an inert element such as argon.
  • phosphine (PH3) or the like may be used as the source gas.
  • the helium may be injected to the second depth Z2 of the helium concentration peak 141 by a method other than plasma doping.
  • Helium ions may be accelerated to an electric field or the like to inject helium to the second depth Z2.
  • the second depth position Z2 may be separated from the lower surface 23 by 80 ⁇ m or more in the depth direction.
  • the second depth position Z2 may be separated from the lower surface 23 by 90 ⁇ m or more, and may be separated by 100 ⁇ m or more.
  • the distance between the first depth position and the second depth position in the depth direction may be 50% or more, 65% or more, and 80% or more of the thickness of the semiconductor substrate 10 in the depth direction. May be
  • FIG. 28 shows another example of the donor concentration distribution, the hydrogen chemical concentration distribution, and the helium chemical concentration distribution in the depth direction of the semiconductor substrate 10.
  • the hydrogen chemical concentration distribution and the helium chemical concentration distribution schematically show only the vicinity of the peak.
  • the first depth Z1 of this example is the same as the example of FIG.
  • the second depth Z2 may be arranged on the upper surface 21 side of the semiconductor substrate 10.
  • the upper surface 21 side refers to a region from the center of the semiconductor substrate 10 in the depth direction to the upper surface 21.
  • the hydrogen chemical concentration distribution may have one or more hydrogen concentration peaks 194 between the first depth Z1 and the second depth Z2. ..
  • the hydrogen concentration peak 194 may be arranged in the buffer region 20 described with reference to FIG.
  • the hydrogen concentration peak 131 may be arranged in the buffer region 20, or may be arranged between the buffer region 20 and the lower surface 23.
  • FIG. 29 is a diagram showing an example of the hydrogen chemical concentration distribution and the argon chemical concentration distribution in the vicinity of the hydrogen concentration peak 131.
  • the hydrogen concentration peak 131 is a peak corresponding to hydrogen injected by plasma doping
  • the hydrogen concentration peak 194 is a peak corresponding to hydrogen injected by a method other than plasma doping.
  • impurities other than hydrogen may be injected in the vicinity of the first depth position Z1.
  • impurities other than hydrogen may be injected in the vicinity of the first depth position Z1.
  • argon gas used for plasma excitation
  • argon may be injected in the vicinity of the first depth position Z1.
  • an argon concentration peak 196 is shown at the depth position Z0.
  • the depth position Z0 may be arranged between the lower surface 23 and the first depth position Z1. Since argon is an element heavier than hydrogen, the argon concentration peak 196 is likely to be formed at a position shallower than the hydrogen concentration peak 131.
  • no peak of the chemical concentration of argon is provided between the first depth position Z1 and the second depth position Z2. Since the hydrogen concentration peak 194 between the first depth position Z1 and the second depth position Z2 is formed by a method other than plasma doping, argon is injected in the vicinity of the hydrogen concentration peak 194. It has not been.
  • the argon chemical concentration between the first depth position Z1 and the second depth position Z2 is smaller than the argon concentration peak 196.
  • the maximum value of the argon chemical concentration between the first depth position Z1 and the second depth position Z2 is less than or equal to the minimum value of the argon chemical concentration between the lower surface 23 and the first depth position Z1. You can
  • a phosphorus concentration peak may be provided between the lower surface 23 and the first depth position Z1.
  • a fluorine concentration peak may be provided between the lower surface 23 and the first depth position Z1, and a boron concentration peak may be provided.
  • the concentration value of the concentration peak of argon, phosphorus, fluorine, or boron may be smaller than the concentration value of the hydrogen concentration peak 131.
  • the concentration value of the concentration peak of argon, phosphorus, fluorine, or boron may be half or less of the concentration value of the hydrogen concentration peak 131, or 1/10 or less.
  • FIG. 30 is a diagram showing another structural example of the semiconductor device 100.
  • the semiconductor device 100 of this example includes a transistor section 70 and a diode section 80, as in the example shown in FIG.
  • the structure of the transistor unit 70 is the same as the example shown in FIG.
  • the transistor section 70 and the diode section 80 are provided adjacent to each other in the X-axis direction.
  • the diode part 80 of this example has a dummy trench part 30 in place of the gate trench part 40, a cathode region 82 in place of the collector region 22, and a emitter region 12 in addition to the structure of the transistor part 70. The difference is that it does not have.
  • the other structure is similar to that of the transistor section 70.
  • the dummy trench section 30 may have the same structure as the gate trench section 40.
  • the dummy trench portion 30 has a dummy insulating film 32 and a dummy conductive portion 34.
  • the dummy insulating film 32 and the dummy conductive portion 34 may have the same structure and material as the gate insulating film 42 and the gate conductive portion 44.
  • the gate conductive portion 44 is electrically connected to the gate electrode, while the dummy conductive portion 34 is electrically connected to the emitter electrode 52.
  • the dummy trench section 30 may also be provided in the transistor section 70. That is, part of the gate trench section 40 in the transistor section 70 may be replaced with the dummy trench section 30.
  • the cathode region 82 is exposed on the lower surface 23 of the semiconductor substrate 10.
  • the cathode region 82 is connected to the collector electrode 54 on the lower surface 23.
  • the cathode region 82 is an N+ type region doped with an N type impurity such as phosphorus.
  • the buffer region 20 may be provided between the cathode region 82 and the drift region 18.
  • the base region 14 may be exposed on the upper surface 21.
  • the base region 14 of the diode portion 80 is electrically connected to the emitter electrode 52. With such a configuration, the diode section 80 functions as a diode.
  • each concentration distribution in the transistor section 70 may be the same as any one of the modes described in FIGS. 1 to 29.
  • the hydrogen chemical concentration distribution in the depth direction of the diode part 80 may be the same as the hydrogen chemical concentration distribution in the depth direction of the transistor part 70.
  • the helium chemical concentration distribution in the depth direction of the diode portion 80 may be the same as the helium chemical concentration distribution in the depth direction of the transistor portion 70.
  • FIG. 31 shows an example of the carrier concentration distribution, the hydrogen chemical concentration distribution, and the boron chemical concentration distribution on the DD line of FIG.
  • the DD line passes through the collector region 22 and a part of the buffer region 20 in the transistor unit 70.
  • the collector region 22 of this example is formed by implanting boron. Boron in the collector region 22 of this example is implanted in a process different from that for hydrogen in the hydrogen concentration peak 131. At least a part of boron in the collector region 22 may be implanted in plasma doping for implanting hydrogen in the hydrogen concentration peak 131.
  • the hydrogen concentration peak 131 was arranged in the buffer region 20.
  • the hydrogen concentration peak 131 in this example is arranged in the cathode region 82 and the collector region 22. Since the doping concentration of the cathode region 82 and the collector region 22 is very high, by providing the hydrogen concentration peak 131 in the cathode region 82 and the collector region 22, even if a high concentration hydrogen donor is generated by the hydrogen concentration peak 131, carrier It is possible to suppress variations in the shape of the concentration distribution. Therefore, it is easy to suppress the influence on the characteristics of the semiconductor device 100.
  • the concentration of the hydrogen concentration peak 131 is set so that the hydrogen donor concentration is sufficiently smaller than the carrier concentration at the first depth position Z1.
  • the activation rate of hydrogen is about 1%.
  • 1% of the hydrogen chemical concentration may be lower than the boron chemical concentration.
  • the peak position of the carrier concentration distribution in the collector region 22 is located closer to the boron chemical concentration peak than the hydrogen concentration peak 131.
  • the peak of the boron chemical concentration is located on the lower surface 23.
  • the peak position of the carrier concentration distribution in the collector region 22 may be the same as the peak position of the chemical concentration of boron.
  • the hydrogen concentration peak 131 may be arranged between the peak of the carrier concentration distribution in the collector region 22 and the buffer region 20. In this example, the peak position of the carrier concentration distribution in the collector region 22 coincides with the lower surface 23. In the buffer region 20, the depth position of the hydrogen concentration peak 194 may coincide with the depth position of the peak 24 of the carrier concentration distribution.
  • FIG. 32 shows an example of the carrier concentration distribution, the hydrogen chemical concentration distribution, and the phosphorus chemical concentration distribution on the line EE of FIG.
  • the EE line passes through the cathode region 82 and a part of the buffer region 20 in the diode section 80.
  • the cathode region 82 of this example is formed by implanting phosphorus. Phosphorus in the cathode region 82 is implanted in a process different from that for hydrogen in the hydrogen concentration peak 131. At least a portion of phosphorus in the cathode region 82 may be implanted in plasma doping for implanting hydrogen in the hydrogen concentration peak 131.
  • the hydrogen concentration peak 131 in this example is arranged in the cathode region 82 and the collector region 22.
  • the concentration of the hydrogen concentration peak 131 is set so that the hydrogen donor concentration is sufficiently smaller than the carrier concentration at the first depth Z1.
  • the activation rate of hydrogen is about 1%.
  • 1% of the hydrogen chemical concentration may be less than the phosphorus chemical concentration.
  • the peak position of the carrier concentration distribution in the cathode region 82 is located closer to the phosphorus chemical concentration peak than the hydrogen concentration peak 131.
  • the phosphorus chemical concentration peak is located on the lower surface 23.
  • the peak position of the carrier concentration distribution in the cathode region 82 may be the same as the peak position of the phosphorus chemical concentration.
  • the hydrogen concentration peak 131 may be arranged between the peak of the carrier concentration distribution in the cathode region 82 and the buffer region 20. In this example, the peak position of the carrier concentration distribution in the cathode region 82 coincides with the lower surface 23. In the buffer region 20, the depth position of the hydrogen concentration peak 194 may coincide with the depth position of the peak 24 of the carrier concentration distribution.
  • FIG. 33 is a diagram showing a part of the method of manufacturing the semiconductor device 100. Before the step shown in FIG. 33, the structure of each trench portion, the emitter region 12, the base region 14, the storage region 16 and the like on the upper surface 21 side may be formed.
  • helium ions are implanted from the lower surface 23 of the semiconductor substrate 10 to the second depth Z2.
  • the injection step S3300 may be the same as the second injection step S1902 in the example of FIG.
  • hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 to the first depth Z1.
  • hydrogen ions are implanted by plasma doping.
  • the dose of hydrogen in the implantation step S3302 may be the same as the dose of hydrogen in the first implantation step S1900 of the example of FIG. Either the injection step S3300 or the injection step S3302 may be performed first.
  • a diffusion step S3304 is performed after the injection step S3300 and the injection step S3302.
  • the spreading step S3304 is similar to the spreading step S1904 in the example of FIG.
  • the crystal defects in the passage region 106 and hydrogen are combined to form a donor.
  • the donor concentration in the passage region 106 can be increased.
  • a grinding step S3306 is performed after the diffusion step S3304.
  • the lower surface 23 side of the semiconductor substrate 10 is ground by chemical mechanical polishing (CMP) or the like.
  • CMP chemical mechanical polishing
  • a range shallower than the first depth Z1 may be ground, or a range deeper than the first depth Z1 may be ground.
  • the region where hydrogen is distributed at a high concentration can be ground, and the amount of hydrogen near the lower surface 23 can be reduced.
  • the lower surface side structure forming step S3308 structures on the lower surface 23 side such as the collector region 22, the cathode region 82, and the buffer region 20 are formed.
  • the vicinity of the lower surface 23 may be laser annealed. Thereby, the vicinity of the lower surface 23 of the semiconductor substrate 10 can be locally heat-treated at a high temperature.
  • a dopant such as hydrogen may be injected into the buffer region 20 after laser annealing. After implanting the dopant in the buffer region 20, the entire semiconductor substrate 10 may be heat-treated in an annealing furnace.
  • FIG. 34 is a diagram showing a part of the method of manufacturing the semiconductor device 100.
  • the manufacturing method of this example is different in that a laser annealing step S3307 is provided instead of the grinding step S3306 of FIG.
  • the other steps are the same as in the example of FIG.
  • the lower surface 23 of the semiconductor substrate 10 is laser-annealed.
  • a laser may be irradiated near the first depth Z1. Thereby, at least a part of hydrogen in the vicinity of the first depth Z1 can be released to the outside of the semiconductor substrate 10. Thereby, the hydrogen chemical concentration in the vicinity of the first depth Z1 can be reduced.
  • the laser may be irradiated so that the hydrogen concentration peak 131 remains, or the laser may be irradiated so that the hydrogen concentration peak 131 does not remain.
  • the semiconductor substrate 10 may have the impurity concentration peaks such as argon shown in FIG.
  • the transistor section 70 may be irradiated with the laser and the diode section 80 may not be irradiated with the laser. Even if a high-concentration hydrogen donor remains on the lower surface 23 of the diode portion 80, the influence on the characteristics is relatively small. In this case, the chemical hydrogen concentration at the first depth Z1 of the diode portion 80 is higher than the chemical hydrogen concentration at the first depth Z1 of the transistor portion 70.
  • the implantation of hydrogen ions to the first depth Z1, the implantation of helium ions to the second depth Z2, and the heat treatment are performed before forming the lower surface side structure. It may be performed after forming the lower surface side structure, or may be performed while forming the lower surface side structure.
  • FIG. 35 shows an example of a step of implanting hydrogen ions to the first depth Z1 and implanting helium ions to the second depth Z2 in the lower surface side structure formation step.
  • the implantation of hydrogen ions to the first depth Z1, the implantation of helium ions to the second depth Z2, and the heat treatment are performed in the buffer region formation step S3504 of forming the buffer region 20.
  • the lower surface side structure forming step may be performed after the upper surface side structure forming step S3500 such as the trench portion.
  • the lower surface side structure forming step includes a collector area forming step S3502 and a buffer area forming step S3504. In FIG. 35, the other steps of the lower surface side structure forming step are omitted.
  • the buffer region forming step S3504 hydrogen ions are implanted into the first depth Z1 and helium ions are implanted into the second depth Z2.
  • the semiconductor substrate 10 is heat-treated to diffuse hydrogen ions and helium ions.
  • a collector electrode forming step S3506 may be performed after the lower surface side structure forming step.
  • FIG. 36 shows another example of the step of implanting hydrogen ions to the first depth Z1 and implanting helium ions to the second depth Z2 in the lower surface side structure formation step.
  • the implantation of hydrogen ions to the first depth Z1 and the heat treatment are performed in the cathode region forming step S3503.
  • the implantation of helium ions to the second depth Z2 and the heat treatment are performed in the buffer region forming step S3506.
  • the lower surface side structure forming step may be performed after the upper surface side structure forming step S3500 such as the trench portion.
  • the lower surface side structure forming step of this example includes a cathode area forming step S3503 and a buffer area forming step S3504. In FIG. 36, the other steps of the lower surface side structure forming step are omitted.
  • the semiconductor device 100 of this example may include a transistor section 70 and a diode section 80.
  • the P-type collector region 22 may be formed in a part of the cathode region 82 by selectively implanting the P-type dopant after forming the cathode region 82 on the entire lower surface 23.
  • a source gas such as PH3 containing an N-type dopant such as phosphorus may be used.
  • hydrogen ions are implanted into the entire lower surface 23 to the first depth Z1.
  • the cathode region 82 may be formed by selectively forming the collector region 22 on the lower surface 23 and then implanting an N-type dopant and hydrogen ions into the entire lower surface 23.
  • the collector region 22 may be preliminarily implanted with a high concentration of P-type dopant so that the conductivity type is not inverted to N-type.
  • the first depth Z1 is arranged in the collector region 22 and the cathode region 82.
  • the step of forming the collector region 22 can be omitted. Further, hydrogen implantation to the second depth Z2 may be performed at the stage of forming the buffer region 20. A collector electrode forming step S3506 may be performed after the lower surface side structure forming step.
  • Field plate 100... Semiconductor device, 106... Passage region, 111... First donor concentration peak, 112, 122, 132, 142, 172... Uphill slope, 113, 123, 133, 143, 173... Downhill slope, 114, 124, 125, 134, 144, 145... Inclination, 116... Gate pad, 118... -Emitter pad, 120... Active part, 121... Second donor concentration peak, 131... Hydrogen concentration peak, 140... Perimeter edge, 141... Helium concentration peak, 150... Flat Regions, 151... Valleys, 161... First example, 162... Second example, 163... Third example, 164... Fourth example, 165... Fifth , 171... Vacancy peak, 174...
  • Channel stopper 175... Vacancy concentration distribution, 180... Base doping region, 181... Non-doping region, 182... Protection Film, 184... Plating layer, 190... Intermediate boundary area, 192... Lifetime control area, 194... Hydrogen concentration peak, 196... Argon concentration peak, 200... Photoresist film

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Abstract

The present invention makes it possible to precisely control the area and donor concentration of a donor region that is generated by the bonding of crystal defects and hydrogen. Provided is a semiconductor device that, in the depth direction, has a hydrogen concentration distribution that has a hydrogen concentration peak, has a helium concentration distribution that has a helium concentration peak, and has a donor concentration distribution that has a first donor concentration peak and a second donor concentration peak, the hydrogen concentration peak and the first donor concentration peak being at a first depth, the helium concentration peak and the second donor concentration peak being at a second depth that is deeper than the first depth relative to a lower surface, and each concentration peak having an upward slope along which concentration values increase from the lower surface toward an upper surface, the value obtained by using the slope of the upward slope of the helium concentration peak to normalize the slope of the upward slope of the second donor concentration peak being smaller than the value obtained by using the slope of the upward slope of the hydrogen concentration peak to normalize the slope of the upward slope of the first donor concentration peak.

Description

半導体装置および製造方法Semiconductor device and manufacturing method
　本発明は、半導体装置および製造方法に関する。 The present invention relates to a semiconductor device and a manufacturing method.
　従来、半導体基板に水素を注入して拡散させることで、拡散領域に存在していた結晶欠陥と水素が結合してドナー化することが知られている（例えば、特許文献１参照）。
　特許文献１　特表２０１６－２０４２２７号公報 Conventionally, it is known that by implanting and diffusing hydrogen into a semiconductor substrate, hydrogen is bonded to the crystal defects existing in the diffusion region to form a donor (see, for example, Patent Document 1).
Patent Document 1 Japanese Patent Publication No. 2016-204227
解決しようとする課題Challenges to be solved
　結晶欠陥と水素が結合することで生じるドナー領域の範囲およびドナー濃度は、精度よく制御できることが好ましい。 It is preferable that the range of the donor region and the donor concentration that are generated by the bonding of crystal defects and hydrogen can be accurately controlled.
一般的開示General disclosure
　上記課題を解決するために、本発明の一つの態様においては、上面および下面を有する半導体基板を備える半導体装置を提供する。半導体基板の上面と下面とを結ぶ深さ方向において、水素濃度分布が水素濃度ピークを有してよい。ヘリウム濃度分布がヘリウム濃度ピークを有してよい。深さ方向において、ドナー濃度分布が第１のドナー濃度ピークと第２のドナー濃度ピークを有してよい。水素濃度ピークと第１のドナー濃度ピークは第１の深さに配置されてよい。ヘリウム濃度ピークと第２のドナー濃度ピークは、下面を基準として第１の深さよりも深い第２の深さに配置されてよい。それぞれの濃度ピークは、下面から上面に向かうにつれて濃度値が増大する上りスロープを有してよい。第２のドナー濃度ピークの上りスロープの傾きを、ヘリウム濃度ピークの上りスロープの傾きで規格化した値が、第１のドナー濃度ピークの上りスロープの傾きを、水素濃度ピークの上りスロープの傾きで規格化した値よりも小さくてよい。 In order to solve the above problems, in one aspect of the present invention, a semiconductor device including a semiconductor substrate having an upper surface and a lower surface is provided. The hydrogen concentration distribution may have a hydrogen concentration peak in the depth direction connecting the upper surface and the lower surface of the semiconductor substrate. The helium concentration distribution may have a helium concentration peak. In the depth direction, the donor concentration distribution may have a first donor concentration peak and a second donor concentration peak. The hydrogen concentration peak and the first donor concentration peak may be arranged at the first depth. The helium concentration peak and the second donor concentration peak may be arranged at a second depth deeper than the first depth with reference to the lower surface. Each concentration peak may have an upward slope where the concentration value increases from the lower surface to the upper surface. The value obtained by normalizing the slope of the upward slope of the second donor concentration peak by the slope of the slope of the helium concentration peak is the slope of the slope of the first donor concentration peak is the slope of the upward slope of the hydrogen concentration peak. It may be smaller than the standardized value.
　それぞれの濃度ピークは、下面から上面に向かうにつれて濃度値が減少する下りスロープを有してよい。ヘリウム濃度ピークは、上りスロープの傾きが、下りスロープの傾きよりも小さくてよい。第２のドナー濃度ピークは、上りスロープの傾きが、下りスロープの傾きよりも小さくてよい。 -Each concentration peak may have a downward slope where the concentration value decreases from the lower surface toward the upper surface. In the helium concentration peak, the slope of the ascending slope may be smaller than the slope of the descending slope. In the second donor concentration peak, the slope of the ascending slope may be smaller than the slope of the descending slope.
　第１の深さと第２の深さとの間におけるドナー濃度分布は、ドナー濃度がほぼ一定の平坦領域を有してよい。平坦領域の深さ方向における長さが、半導体基板の深さ方向における厚みの１０％以上であってよい。 The donor concentration distribution between the first depth and the second depth may have a flat region where the donor concentration is almost constant. The length of the flat region in the depth direction may be 10% or more of the thickness of the semiconductor substrate in the depth direction.
　第１の深さと第２の深さとの間におけるドナー濃度分布は、ドナー濃度がほぼ一定の平坦領域を有してよい。平坦領域の深さ方向における長さが１０μｍ以上であってよい。 The donor concentration distribution between the first depth and the second depth may have a flat region where the donor concentration is almost constant. The length of the flat region in the depth direction may be 10 μm or more.
　平坦領域のドナー濃度の最小値は、半導体基板のドナー濃度よりも高くてよい。 The minimum donor concentration of the flat region may be higher than the donor concentration of the semiconductor substrate.
　第１の深さと第２の深さとの間におけるドナー濃度の最小値は、半導体基板のドナー濃度よりも高くてよい。 The minimum value of the donor concentration between the first depth and the second depth may be higher than the donor concentration of the semiconductor substrate.
　ヘリウム濃度ピークの濃度値が、水素濃度ピークの濃度値よりも小さくてよい。 The concentration value of the helium concentration peak may be smaller than the concentration value of the hydrogen concentration peak.
　半導体装置は、半導体基板に設けられたＮ型のドリフト領域を備えてよい。半導体装置は、半導体基板において上面に接して設けられ、ドリフト領域よりもドナー濃度の高いエミッタ領域を備えてよい。半導体装置は、エミッタ領域とドリフト領域との間に設けられたＰ型のベース領域を備えてよい。半導体装置は、半導体基板において下面に接して設けられたＰ型のコレクタ領域を備えてよい。コレクタ領域とドリフト領域との間に設けられ、ドリフト領域よりもドナー濃度の高い１つ以上のドナー濃度ピークを有するＮ型のバッファ領域を備えてよい。第１のドナー濃度ピークは、バッファ領域のドナー濃度ピークであってよい。 The semiconductor device may include an N-type drift region provided on the semiconductor substrate. The semiconductor device may include an emitter region provided in contact with the upper surface of the semiconductor substrate and having a donor concentration higher than that of the drift region. The semiconductor device may include a P-type base region provided between the emitter region and the drift region. The semiconductor device may include a P-type collector region provided in contact with the lower surface of the semiconductor substrate. An N-type buffer region, which is provided between the collector region and the drift region and has one or more donor concentration peaks having a higher donor concentration than the drift region, may be provided. The first donor concentration peak may be a buffer region donor concentration peak.
　半導体装置は、ベース領域とドリフト領域との間に設けられ、ドリフト領域よりもドナー濃度の高い１つ以上のドナー濃度ピークを有する蓄積領域を備えてよい。第２のドナー濃度ピークは、蓄積領域のドナー濃度ピークであってよい。 The semiconductor device may include an accumulation region provided between the base region and the drift region and having one or more donor concentration peaks having a higher donor concentration than the drift region. The second donor concentration peak may be the donor concentration peak of the accumulation region.
　蓄積領域は、第２のドナー濃度ピーク以外に、水素以外のドナーによるドナー濃度ピークを有してよい。 The accumulation region may have a donor concentration peak due to a donor other than hydrogen, in addition to the second donor concentration peak.
　第２のドナー濃度ピークは、バッファ領域と蓄積領域との間に配置されていてよい。 The second donor concentration peak may be arranged between the buffer area and the accumulation area.
　半導体装置は、半導体基板の上面に設けられたゲートトレンチ部を備えてよい。第２のドナー濃度ピークは、ゲートトレンチ部の底部と、半導体基板の上面との間に配置されていてよい。 The semiconductor device may include a gate trench portion provided on the upper surface of the semiconductor substrate. The second donor concentration peak may be arranged between the bottom of the gate trench portion and the upper surface of the semiconductor substrate.
　半導体装置は、半導体基板に設けられた活性部を備えてよい。半導体装置は、半導体基板の上面視において活性部を囲んで設けられたエッジ終端構造部を備えてよい。半導体基板は、ヘリウム濃度ピークの位置に注入されたヘリウムが通過した通過領域を有してよい。深さ方向において、エッジ終端構造部に設けられた通過領域は、活性部に設けられた通過領域よりも短いか、または、エッジ終端構造部には通過領域が設けられていなくてよい。 The semiconductor device may include an active part provided on the semiconductor substrate. The semiconductor device may include an edge termination structure portion provided so as to surround the active portion in a top view of the semiconductor substrate. The semiconductor substrate may have a passage region through which the injected helium passes at the position of the helium concentration peak. In the depth direction, the pass region provided in the edge termination structure may be shorter than the pass region provided in the active portion, or the pass region may not be provided in the edge termination structure.
　半導体装置は、半導体基板に設けられたトランジスタ部およびダイオード部を備えてよい。深さ方向において、ダイオード部に設けられた通過領域は、トランジスタ部に設けられた通過領域よりも短いか、または、ダイオード部には通過領域が設けられていなくてよい。 The semiconductor device may include a transistor section and a diode section provided on the semiconductor substrate. In the depth direction, the pass region provided in the diode part may be shorter than the pass region provided in the transistor part, or the pass region may not be provided in the diode part.
　深さ方向において、トランジスタ部に設けられた通過領域は、ダイオード部に設けられた通過領域よりも短いか、または、トランジスタ部には通過領域が設けられていなくてよい。 In the depth direction, the passage area provided in the transistor portion is shorter than the passage area provided in the diode portion, or the passage area may not be provided in the transistor portion.
　第１の深さが、下面から深さ方向に５μｍ以下の範囲に含まれていてよい。 The first depth may be included in a range of 5 μm or less from the lower surface in the depth direction.
　水素濃度ピークにおけるドナー濃度が、１×１０１５／ｃｍ３以上、１×１０１７／ｃｍ３以下であってよい。 The donor concentration at the hydrogen concentration peak may be 1×10 15 /cm 3 or more and 1×10 17 /cm 3 or less.
　本発明の第２の態様においては、上面および下面を有する半導体基板を備える半導体装置を提供する。半導体基板の上面と下面とを結ぶ深さ方向における水素濃度分布が、下面から深さ方向に５μｍ以下の範囲に配置された水素濃度ピークと、水素濃度ピークよりも上面側に配置されたヘリウム濃度ピークとを有してよい。 According to a second aspect of the present invention, there is provided a semiconductor device including a semiconductor substrate having an upper surface and a lower surface. The hydrogen concentration distribution in the depth direction connecting the upper surface and the lower surface of the semiconductor substrate is a hydrogen concentration peak arranged in the range of 5 μm or less in the depth direction from the lower surface, and a helium concentration arranged on the upper surface side of the hydrogen concentration peak. And a peak.
　半導体基板は、下面と水素濃度ピークの間に不純物濃度ピークを有し、不純物はアルゴンまたはフッ素であってよい。 The semiconductor substrate has an impurity concentration peak between the lower surface and the hydrogen concentration peak, and the impurity may be argon or fluorine.
　本発明の第３の態様においては、第１の態様に係る半導体装置の製造方法を提供する。製造方法は、半導体基板の下面から第１の深さに水素を注入する第１注入段階を備えてよい。製造方法は、半導体基板の下面から第２の深さにヘリウムを注入して、ヘリウムが通過した通過領域を形成する第２注入段階を備えてよい。製造方法は、半導体基板を熱処理して、第１の深さに注入された水素を、通過領域に拡散させる拡散段階を備えてよい。拡散段階において熱処理された半導体基板において、通過領域のドナー濃度の最小値が、水素を注入する前の半導体基板のドナー濃度よりも高くなるように、第１注入段階における水素のドーズ量を定めてよい。 A third aspect of the present invention provides a method for manufacturing a semiconductor device according to the first aspect. The manufacturing method may include a first implantation step of implanting hydrogen from the lower surface of the semiconductor substrate to the first depth. The manufacturing method may include a second implantation step of implanting helium from the lower surface of the semiconductor substrate to a second depth to form a passage region through which helium has passed. The manufacturing method may include a diffusion step in which the semiconductor substrate is heat-treated to diffuse the hydrogen implanted into the first depth into the passage region. In the semiconductor substrate heat-treated in the diffusion step, the dose amount of hydrogen in the first implantation step is set so that the minimum value of the donor concentration of the passage region is higher than the donor concentration of the semiconductor substrate before the implantation of hydrogen. Good.
　第１注入段階では、半導体基板における水素の拡散係数と、第２の深さから定まる最小ドーズ量以上のドーズ量で、水素を注入してよい。 In the first implantation step, hydrogen may be implanted at a dose amount that is equal to or higher than the minimum dose amount determined by the diffusion coefficient of hydrogen in the semiconductor substrate and the second depth.
　半導体基板はシリコン基板であり、下面からの第２の深さをｘ（ｃｍ）とした場合に、第１注入段階における水素のドーズ量Ｑ（／ｃｍ２）が下式を満たしてよい。
　Ｑ≧１．６×１０１３×ｅ０．０６ｘ The semiconductor substrate is a silicon substrate, and when the second depth from the lower surface is x (cm), the hydrogen dose Q (/cm 2 ) in the first implantation step may satisfy the following formula.
Q≧1.6×10 13 ×e 0.06x
　第１注入段階において、プラズマドーピングにより、第１の深さに水素を注入してよい。 In the first implantation step, hydrogen may be implanted to the first depth by plasma doping.
　プラズマドーピングの後に、半導体基板の下面を研削してよい。 After plasma doping, the lower surface of the semiconductor substrate may be ground.
　プラズマドーピングの後に、半導体基板の下面をレーザーアニールしてよい。 After plasma doping, the lower surface of the semiconductor substrate may be laser annealed.
　なお、上記の発明の概要は、本発明の必要な特徴の全てを列挙したものではない。また、これらの特徴群のサブコンビネーションもまた、発明となりうる。 The above summary of the invention does not enumerate all necessary features of the invention. Further, a sub-combination of these feature groups can also be an invention.
半導体装置１００の一例を示す断面図である。3 is a cross-sectional view showing an example of the semiconductor device 100. FIG. 図１のＡ－Ａ線に示した位置における、深さ方向の水素濃度分布、ヘリウム濃度分布、ドナー濃度分布および空孔欠陥濃度分布１７５を示している。The hydrogen concentration distribution, the helium concentration distribution, the donor concentration distribution, and the vacancy defect concentration distribution 175 in the depth direction are shown at the position indicated by the line AA in FIG. 水素濃度ピーク１３１と、第１のドナー濃度ピーク１１１との関係を説明する図である。It is a figure explaining the relationship between the hydrogen concentration peak 131 and the 1st donor concentration peak 111. ヘリウム濃度ピーク１４１と、第２のドナー濃度ピーク１２１との関係を説明する図である。It is a figure explaining the relationship between the helium concentration peak 141 and the 2nd donor concentration peak 121. 上りスロープ１４２の傾きを説明する図である。It is a figure explaining the inclination of the uphill slope 142. 上りスロープ１１２の傾きの規格化の他の定義を説明する図である。It is a figure explaining the other definition of the standardization of the inclination of the uphill slope 112. 上りスロープ１２２の傾きの規格化の他の定義を説明する図である。It is a figure explaining other definitions of standardization of the slope of uphill slope 122. 平坦領域１５０を説明する図である。It is a figure explaining the flat area|region 150. 半導体装置１００の構造例を示す図である。3 is a diagram showing a structural example of a semiconductor device 100. FIG. 図６のＢ－Ｂ線の位置における、深さ方向のキャリア濃度分布の一例を示す図である。FIG. 7 is a diagram showing an example of carrier concentration distribution in the depth direction at the position of line BB in FIG. 6. 半導体装置１００の他の構造例を示す図である。FIG. 6 is a diagram showing another structural example of the semiconductor device 100. 図８のＣ－Ｃ線の位置における、深さ方向のキャリア濃度分布の一例を示す図である。FIG. 9 is a diagram showing an example of a carrier concentration distribution in the depth direction at the position of line CC in FIG. 8. 図１のＡ－Ａ線に示した位置における、深さ方向の水素濃度分布、ヘリウム濃度分布およびキャリア濃度分布を示している。The hydrogen concentration distribution, the helium concentration distribution, and the carrier concentration distribution in the depth direction at the position indicated by the line AA in FIG. 1 are shown. 半導体基板１０の上面２１における各要素の配置例を示す図である。FIG. 5 is a diagram showing an arrangement example of each element on the upper surface 21 of the semiconductor substrate 10. 図１１におけるｃ－ｃ'断面の一例を示す図である。FIG. 12 is a diagram showing an example of a cc′ cross section in FIG. 11. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. ヘリウムイオンを半導体基板１０に侵入させないための、フォトレジスト膜２００の最小膜厚Ｍを説明する図である。FIG. 6 is a diagram illustrating a minimum film thickness M of the photoresist film 200 for preventing helium ions from entering the semiconductor substrate 10. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. 通過領域１０６の他の配置例を示す図である。It is a figure which shows the other example of arrangement|positioning of the passage area 106. FIG. 半導体装置１００の製造方法において、通過領域１０６を形成する工程を示す図である。FIG. 6 is a diagram showing a step of forming a passage region 106 in the method of manufacturing the semiconductor device 100. 拡散段階Ｓ１９０４の後の半導体基板１０における、キャリア濃度分布の一例を示す図である。It is a figure which shows an example of carrier concentration distribution in the semiconductor substrate 10 after the diffusion step S1904. 水素の拡散係数Ｄと、第１のドーズ量Ｑとの関係を示す図である。It is a figure which shows the relationship between the diffusion coefficient D of hydrogen, and the 1st dose amount Q. 拡散係数Ｄと、アニール温度Ｔとの関係を示す図である。It is a figure which shows the relationship between the diffusion coefficient D and the annealing temperature T. 水素の拡散深さと、第１のドーズ量との関係を示す図である。It is a figure which shows the relationship between the diffusion depth of hydrogen, and the 1st dose amount. 拡散係数Ｄと拡散深さｘの関係を示す図である。It is a figure which shows the relationship between the diffusion coefficient D and the diffusion depth x. アニール温度毎の、最小ドーズ量を規定する直線を示す図である。It is a figure which shows the straight line which defines the minimum dose amount for every annealing temperature. 第２のドーズ量と、第１のドーズ量の最小ドーズ量との関係を示す図である。It is a figure which shows the relationship between the 2nd dose amount and the minimum dose amount of a 1st dose amount. 第１の深さＺ１の一例を説明する図である。It is a figure explaining an example of the 1st depth Z1. 半導体基板１０の深さ方向におけるドナー濃度分布、水素化学濃度分布およびヘリウム化学濃度分布の他の例を示している。5 shows another example of the donor concentration distribution, the hydrogen chemical concentration distribution, and the helium chemical concentration distribution in the depth direction of the semiconductor substrate 10. 水素濃度ピーク１３１の近傍における、水素化学濃度分布と、アルゴン化学濃度分布の一例を示す図である。FIG. 3 is a diagram showing an example of a hydrogen chemical concentration distribution and an argon chemical concentration distribution in the vicinity of a hydrogen concentration peak 131. 半導体装置１００の他の構造例を示す図である。FIG. 6 is a diagram showing another structural example of the semiconductor device 100. 図３０のＤ－Ｄ線における、キャリア濃度分布、水素化学濃度分布およびボロン化学濃度分布の一例を示している。30 shows an example of carrier concentration distribution, hydrogen chemical concentration distribution, and boron chemical concentration distribution in the DD line of FIG. 図３０のＥ－Ｅ線における、キャリア濃度分布、水素化学濃度分布およびリン化学濃度分布の一例を示している。31 shows an example of the carrier concentration distribution, the hydrogen chemical concentration distribution, and the phosphorus chemical concentration distribution on the line EE of FIG. 半導体装置１００の製造方法の一部の工程を示す図である。FIG. 7 is a diagram showing a part of the method of manufacturing the semiconductor device 100. 半導体装置１００の製造方法の一部の工程を示す図である。FIG. 7 is a diagram showing a part of the method of manufacturing the semiconductor device 100. 下面側構造形成段階において、第１の深さＺ１に水素イオンを注入し、第２の深さＺ２にヘリウムイオンを注入する工程の一例を示す。An example of a step of implanting hydrogen ions to the first depth Z1 and implanting helium ions to the second depth Z2 in the lower surface side structure formation step will be shown. 下面側構造形成段階において、第１の深さＺ１に水素イオンを注入し、第２の深さＺ２にヘリウムイオンを注入する工程の他の例を示す。Another example of the step of implanting hydrogen ions to the first depth Z1 and implanting helium ions to the second depth Z2 in the lower surface side structure formation step will be described.
　以下、発明の実施の形態を通じて本発明を説明するが、以下の実施形態は請求の範囲にかかる発明を限定するものではない。また、実施形態の中で説明されている特徴の組み合わせの全てが発明の解決手段に必須であるとは限らない。 Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are essential to the solving means of the invention.
　本明細書においては半導体基板の深さ方向と平行な方向における一方の側を「上」、他方の側を「下」と称する。基板、層またはその他の部材の２つの主面のうち、一方の面を上面、他方の面を下面と称する。「上」、「下」の方向は、重力方向または半導体装置の実装時における方向に限定されない。 In this specification, one side in the direction parallel to the depth direction of the semiconductor substrate is called "upper" and the other side is called "lower". Of the two main surfaces of the substrate, layer or other member, one surface is called the upper surface and the other surface is called the lower surface. The “up” and “down” directions are not limited to the gravity direction or the direction when the semiconductor device is mounted.
　本明細書では、Ｘ軸、Ｙ軸およびＺ軸の直交座標軸を用いて技術的事項を説明する場合がある。直交座標軸は、構成要素の相対位置を特定するに過ぎず、特定の方向を限定するものではない。例えば、Ｚ軸は地面に対する高さ方向を限定して示すものではない。なお、＋Ｚ軸方向と－Ｚ軸方向とは互いに逆向きの方向である。正負を記載せず、Ｚ軸方向と記載した場合、＋Ｚ軸および－Ｚ軸に平行な方向を意味する。 In this specification, technical matters may be explained using orthogonal coordinate axes of the X axis, Y axis, and Z axis. The Cartesian coordinate axes only specify the relative positions of the components and do not limit the specific directions. For example, the Z-axis does not limit the height direction to the ground. The +Z axis direction and the −Z axis direction are directions opposite to each other. When the positive and negative signs are not described and the Z axis direction is described, it means a direction parallel to the +Z axis and the −Z axis.
　本明細書において「同一」または「等しい」のように称した場合、製造ばらつき等に起因する誤差を有する場合も含んでよい。当該誤差は、例えば１０％以内である。 When referred to in this specification as “same” or “equal”, it may include cases where there is an error due to manufacturing variations or the like. The error is within 10%, for example.
　本明細書において化学濃度とは、活性化の状態によらずに測定される不純物の濃度を指す。化学濃度は、例えば二次イオン質量分析法（ＳＩＭＳ）により計測できる。本明細書において、ドナーおよびアクセプタの濃度差を、ドナーまたはアクセプタのうちの多い方の濃度とする場合がある。当該濃度差は、電圧－容量測定法（ＣＶ法）により測定できる。また、拡がり抵抗測定法（ＳＲ）により計測されるキャリア濃度を、ドナーまたはアクセプタの濃度としてよい。また、ドナーまたはアクセプタの濃度分布がピークを有する場合、当該ピーク値を当該領域におけるドナーまたはアクセプタの濃度としてよい。ドナーまたはアクセプタが存在する領域におけるドナーまたはアクセプタの濃度がほぼ均一な場合等においては、当該領域におけるドナーまたはアクセプタ濃度の平均値をドナーまたはアクセプタ濃度としてよい。本明細書の単位系は、特に断りがなければＳＩ単位系である。長さの単位をｃｍで表示することがあるが、諸計算はメートル（ｍ）に換算してから行ってよい。 In the present specification, the chemical concentration refers to the concentration of impurities measured regardless of the activation state. The chemical concentration can be measured by, for example, secondary ion mass spectrometry (SIMS). In this specification, the concentration difference between the donor and the acceptor may be the concentration of the larger one of the donor and the acceptor. The concentration difference can be measured by a voltage-capacitance measuring method (CV method). Further, the carrier concentration measured by the spread resistance measuring method (SR) may be the concentration of the donor or the acceptor. When the concentration distribution of the donor or the acceptor has a peak, the peak value may be the concentration of the donor or the acceptor in the region. In a case where the concentration of the donor or acceptor in the region where the donor or acceptor exists is substantially uniform, the average value of the donor or acceptor concentration in the region may be the donor or acceptor concentration. Unit systems herein are SI unit systems unless otherwise noted. Although the unit of length may be displayed in cm, various calculations may be performed after converting to meters (m).
　図１は、半導体装置１００の一例を示す断面図である。半導体装置１００は半導体基板１０を備える。半導体基板１０は、半導体材料で形成された基板である。一例として半導体基板１０はシリコン基板である。半導体基板１０は、製造時に注入された不純物等によって定まるドナー濃度を有する。本例の半導体基板１０の導電型はＮ－型である。本明細書では、半導体基板１０におけるドナー濃度を基板濃度と称する場合がある。 FIG. 1 is a sectional view showing an example of a semiconductor device 100. The semiconductor device 100 includes a semiconductor substrate 10. The semiconductor substrate 10 is a substrate made of a semiconductor material. As an example, the semiconductor substrate 10 is a silicon substrate. The semiconductor substrate 10 has a donor concentration that is determined by impurities and the like that are injected at the time of manufacturing. The conductivity type of the semiconductor substrate 10 of this example is N-type. In this specification, the donor concentration in the semiconductor substrate 10 may be referred to as the substrate concentration.
　半導体基板１０は、上面２１および下面２３を有する。上面２１および下面２３は、半導体基板１０の２つの主面である。本明細書では、上面２１および下面２３と平行な面における直交軸をＸ軸およびＹ軸、上面２１および下面２３と垂直な軸をＺ軸とする。半導体基板１０には、ＩＧＢＴまたはＦＷＤ等の半導体素子が形成されているが、図１ではこれらの素子構造を省略している。 The semiconductor substrate 10 has an upper surface 21 and a lower surface 23. The upper surface 21 and the lower surface 23 are two main surfaces of the semiconductor substrate 10. In this specification, the orthogonal axes in the plane parallel to the upper surface 21 and the lower surface 23 are the X axis and the Y axis, and the axis perpendicular to the upper surface 21 and the lower surface 23 is the Z axis. Although semiconductor elements such as IGBT and FWD are formed on the semiconductor substrate 10, these element structures are omitted in FIG.
　半導体基板１０には、下面２３側から水素イオンおよびヘリウムイオンが注入されている。本例の水素イオンはプロトンである。水素イオンは、半導体基板１０の深さ方向（Ｚ軸方向）において深さＺ１に注入されている。ヘリウムイオンは、深さＺ２に注入されている。本例では、２つの深さのうち、下面２３に近い方を第１の深さＺ１とし、下面２３から見て第１の深さＺ１よりも深い方を第２の深さＺ２とする。図１においては、注入された水素およびヘリウムを×印で模式的に示しているが、水素およびヘリウムは注入位置Ｚ１、Ｚ２の周囲にも分布する。 Hydrogen ions and helium ions are implanted into the semiconductor substrate 10 from the lower surface 23 side. The hydrogen ion in this example is a proton. Hydrogen ions are implanted to a depth Z1 in the depth direction (Z axis direction) of the semiconductor substrate 10. Helium ions are implanted at the depth Z2. In this example, of the two depths, the one closer to the lower surface 23 is the first depth Z1 and the one deeper than the first depth Z1 when viewed from the lower surface 23 is the second depth Z2. In FIG. 1, the injected hydrogen and helium are schematically shown by X, but hydrogen and helium are also distributed around the injection positions Z1 and Z2.
　第１の深さＺ１は、半導体基板１０の深さ方向において下面２３側に配置されてよい。例えば第１の深さＺ１は、下面２３を基準として、半導体基板１０の厚みの半分以下の範囲に配置されていてよく、半導体基板１０の厚みの１／４以下の範囲に配置されていてもよい。第２の深さＺ２は、半導体基板１０の深さ方向において上面２１側に配置されてよい。例えば第２の深さＺ２は、上面２１を基準として、半導体基板１０の厚みの半分以下の範囲に配置されていてよく、半導体基板１０の厚みの１／４以下の範囲に配置されていてもよい。ただし、第１の深さＺ１および第２の深さＺ２はこれらの範囲に限定されない。 The first depth Z1 may be arranged on the lower surface 23 side in the depth direction of the semiconductor substrate 10. For example, the first depth Z1 may be arranged in the range of half the thickness of the semiconductor substrate 10 or less with respect to the lower surface 23, and may be arranged in the range of ¼ or less of the thickness of the semiconductor substrate 10. Good. The second depth Z2 may be arranged on the upper surface 21 side in the depth direction of the semiconductor substrate 10. For example, the second depth Z2 may be arranged in the range of half or less of the thickness of the semiconductor substrate 10 with the upper surface 21 as a reference, and may be arranged in the range of ¼ or less of the thickness of the semiconductor substrate 10. Good. However, the first depth Z1 and the second depth Z2 are not limited to these ranges.
　第２の深さＺ２に注入されたヘリウムイオンは、下面２３から第２の深さＺ２までの通過領域１０６を通過する。通過領域１０６には、ヘリウムイオンが通過したことによって空孔（Ｖ）、複空孔（ＶＶ）等の空孔欠陥が発生する。本明細書では、特に言及がなければ空孔は複空孔も含むものとする。通過領域１０６における空孔密度は、第２の深さＺ２に注入するヘリウムイオンのドーズ量等で調整できる。 The helium ions implanted to the second depth Z2 pass through the passage region 106 from the lower surface 23 to the second depth Z2. In the passage area 106, vacancy defects such as vacancies (V) and compound vacancies (VV) occur due to the passage of helium ions. In the present specification, the pores include double pores unless otherwise specified. The void density in the passage region 106 can be adjusted by the dose amount of the helium ions implanted into the second depth Z2.
　第１の深さＺ１に水素イオンを注入した後に半導体基板１０を熱処理することで、第１の深さＺ１に注入された水素が、通過領域１０６に拡散する。通過領域１０６に存在する空孔（Ｖ）および酸素（Ｏ）と水素（Ｈ）とが結合することで、ＶＯＨ欠陥が形成される。ＶＯＨ欠陥は、電子を供給するドナーとして機能する。これにより、通過領域１０６のドナー濃度を、半導体基板１０の基となる半導体インゴットの製造時におけるドナー濃度Ｄｂ（または比抵抗、ベースドーピング濃度）よりも高くすることができる。従って、半導体基板１０に形成される素子が有するべき特性に応じて、半導体基板１０のドナー濃度を容易に調整できる。なお、特に断りがなければ、本明細書では、水素の化学濃度分布に相似する分布を有するＶＯＨ欠陥も、通過領域１０６の空孔欠陥の分布に相似するＶＯＨ欠陥も、水素ドナー、またはドナーとしての水素と称する。 By heat-treating the semiconductor substrate 10 after implanting hydrogen ions into the first depth Z1, the hydrogen implanted into the first depth Z1 diffuses into the passage region 106. VOH defects are formed by the bonding of vacancies (V) existing in the passage region 106 and oxygen (O) with hydrogen (H). The VOH defect functions as a donor that supplies electrons. As a result, the donor concentration of the passage region 106 can be made higher than the donor concentration Db (or the specific resistance or the base doping concentration) at the time of manufacturing the semiconductor ingot which is the base of the semiconductor substrate 10. Therefore, the donor concentration of the semiconductor substrate 10 can be easily adjusted according to the characteristics that the element formed on the semiconductor substrate 10 should have. Unless otherwise specified, in this specification, VOH defects having a distribution similar to the chemical concentration distribution of hydrogen and VOH defects similar to the distribution of vacancy defects in the passage region 106 are used as hydrogen donors or donors. Of hydrogen.
　なお、ベースドーピング濃度Ｄｂを設定するためのドーパントは、半導体インゴット製造時に添加するドーパントである。一例として半導体インゴットがシリコンの場合、ｎ型のならリン、アンチモン、ヒ素であり、ｐ型ならホウ素、アルミニウムなどでよい。シリコン以外の化合物半導体、酸化物半導体の場合も、それぞれのドーパントであってよい。また、半導体インゴットの製造方法は、フロートゾーン（ＦＺ）法、チョクラルスキー（ＣＺ）法、磁場印加チョクラルスキー（ＭＣＺ）法のいずれであってよい。 Note that the dopant for setting the base doping concentration Db is a dopant added at the time of manufacturing a semiconductor ingot. As an example, when the semiconductor ingot is silicon, n-type may be phosphorus, antimony, or arsenic, and p-type may be boron, aluminum, or the like. In the case of compound semiconductors other than silicon and oxide semiconductors, the respective dopants may be used. The method for manufacturing the semiconductor ingot may be any of the float zone (FZ) method, the Czochralski (CZ) method, and the magnetic field application Czochralski (MCZ) method.
　通常は、半導体基板１０に形成すべき素子の特性、特に定格電圧または耐圧に対応させて、ベースドーピング濃度Ｄｂを有する半導体基板１０を準備しなければならない。これに対して、図１に示した半導体装置１００によれば、水素イオンおよびヘリウムイオンのドーズ量および注入深さを制御することで、半導体装置１００完成時の半導体基板１０のドナー濃度および通過領域１０６の範囲を、ベースドーピング濃度Ｄｂよりも部分的に高くできる。このため、ベースドーピング濃度の異なる半導体基板１０を用いても、所定の定格電圧または耐圧特性の素子を形成できる。また、半導体基板１０の製造時におけるドナー濃度のバラツキは比較的に大きいが、水素イオンおよびヘリウムイオンのドーズ量は比較的に高精度に制御できる。このため、ヘリウムイオンを注入することで生じる空孔（Ｖ）の濃度も高精度に制御でき、通過領域１０６のドナー濃度を高精度に制御できる。 Normally, the semiconductor substrate 10 having the base doping concentration Db must be prepared in accordance with the characteristics of the element to be formed on the semiconductor substrate 10, particularly the rated voltage or the breakdown voltage. On the other hand, according to the semiconductor device 100 shown in FIG. 1, by controlling the dose amount and implantation depth of hydrogen ions and helium ions, the donor concentration and the passage region of the semiconductor substrate 10 when the semiconductor device 100 is completed. The range of 106 can be partially higher than the base doping concentration Db. Therefore, even if the semiconductor substrate 10 having different base doping concentrations is used, an element having a predetermined rated voltage or withstand voltage characteristic can be formed. Further, although the variation in the donor concentration at the time of manufacturing the semiconductor substrate 10 is relatively large, the dose amounts of hydrogen ions and helium ions can be controlled with relatively high accuracy. Therefore, the concentration of vacancies (V) generated by implanting helium ions can be controlled with high precision, and the donor concentration of the passage region 106 can be controlled with high precision.
　図２は、図１のＡ－Ａ線に示した位置における、深さ方向の水素濃度分布、ヘリウム濃度分布、ドナー濃度分布および空孔欠陥濃度分布１７５を示している。図２の横軸は、下面２３からの深さ位置を示しており、縦軸は、単位体積当たりの水素濃度、ヘリウム濃度およびドナー濃度および空孔欠陥濃度を対数軸で示している。なお、空孔欠陥濃度分布１７５については、水素イオンおよびヘリウムイオンをイオン注入した直後の分布である。半導体装置１００が完成したときには、イオン注入した直後に比べて空孔は減少または消滅しており、図２とは異なる濃度分布を示す。図２における水素濃度およびヘリウム濃度は、例えばＳＩＭＳ法で計測される化学濃度である。図２におけるドナー濃度は、例えばＣＶ法またはＳＲ法で計測される、電気的に活性化したドーピング濃度である。図２では、水素濃度分布、ヘリウム濃度分布および空孔欠陥濃度分布１７５を破線で示し、ドナー濃度分布を実線で示している。 FIG. 2 shows the hydrogen concentration distribution, the helium concentration distribution, the donor concentration distribution, and the vacancy defect concentration distribution 175 in the depth direction at the position shown by the line AA in FIG. The horizontal axis of FIG. 2 represents the depth position from the lower surface 23, and the vertical axis represents the hydrogen concentration, the helium concentration, the donor concentration, and the vacancy defect concentration per unit volume on the logarithmic axis. The vacancy defect concentration distribution 175 is a distribution immediately after ion implantation of hydrogen ions and helium ions. When the semiconductor device 100 is completed, vacancies are reduced or disappeared as compared with immediately after the ion implantation, and the concentration distribution different from that in FIG. 2 is shown. The hydrogen concentration and the helium concentration in FIG. 2 are chemical concentrations measured by the SIMS method, for example. The donor concentration in FIG. 2 is an electrically activated doping concentration measured by, for example, the CV method or the SR method. In FIG. 2, the hydrogen concentration distribution, the helium concentration distribution, and the vacancy defect concentration distribution 175 are shown by broken lines, and the donor concentration distribution is shown by a solid line.
　水素濃度分布は、水素濃度ピーク１３１を有する。ヘリウム濃度分布は、ヘリウム濃度ピーク１４１を有する。水素濃度ピーク１３１は、第１の深さＺ１において極大値を示している。ヘリウム濃度ピーク１４１は、第２の深さＺ２において極大値を示している。 The hydrogen concentration distribution has a hydrogen concentration peak 131. The helium concentration distribution has a helium concentration peak 141. The hydrogen concentration peak 131 has a maximum value at the first depth Z1. The helium concentration peak 141 has a maximum value at the second depth Z2.
　ドナー濃度分布は、第１のドナー濃度ピーク１１１および第２のドナー濃度ピーク１２１を有する。第１のドナー濃度ピーク１１１は、第１の深さＺ１において極大値を示している。第２のドナー濃度ピーク１２１は、第２の深さＺ２において極大値を示している。ただし、第１のドナー濃度ピーク１１１が極大値を示す位置は、第１の深さＺ１と厳密に一致していなくともよい。例えば、第１の深さＺ１を基準とした水素濃度ピーク１３１の半値全幅の範囲内に、第１のドナー濃度ピーク１１１が極大値を示す位置が含まれていれば、第１のドナー濃度ピーク１１１が実質的に第１の深さＺ１に配置されているとしてよい。同様に、第２の深さＺ２を基準としたヘリウム濃度ピーク１４１の半値全幅の範囲内に、第２のドナー濃度ピーク１２１が極大値を示す位置が含まれていれば、第２のドナー濃度ピーク１２１が実質的に第２の深さＺ２に配置されているとしてよい。 The donor concentration distribution has a first donor concentration peak 111 and a second donor concentration peak 121. The first donor concentration peak 111 has a maximum value at the first depth Z1. The second donor concentration peak 121 has a maximum value at the second depth Z2. However, the position where the first donor concentration peak 111 has the maximum value does not have to be exactly the same as the first depth Z1. For example, if the position where the first donor concentration peak 111 has the maximum value is included within the full width at half maximum of the hydrogen concentration peak 131 based on the first depth Z1, the first donor concentration peak 111 may be disposed substantially at the first depth Z1. Similarly, if the position where the second donor concentration peak 121 has the maximum value is included within the full width at half maximum of the helium concentration peak 141 based on the second depth Z2, the second donor concentration is increased. The peak 121 may be located substantially at the second depth Z2.
　空孔欠陥濃度分布１７５は、水素濃度ピーク１３１に対応した第１の空孔濃度ピークと、ヘリウム濃度ピーク１４１に対応した第２の空孔濃度ピーク（空孔濃度ピーク１７１）を有する。ただし、第１の空孔濃度ピークについては図示を省略する。空孔濃度ピーク１７１は、第２の深さＺ２において極大値を示している。 The vacancy defect concentration distribution 175 has a first vacancy concentration peak corresponding to the hydrogen concentration peak 131 and a second vacancy concentration peak (vacancy concentration peak 171) corresponding to the helium concentration peak 141. However, illustration of the first vacancy concentration peak is omitted. The vacancy concentration peak 171 has a maximum value at the second depth Z2.
　それぞれの濃度ピークは、半導体基板１０の下面２３から上面２１に向かうにつれて、濃度値が増大する上りスロープと、濃度値が減少する下りスロープとを有する。本例では、水素濃度ピーク１３１は上りスロープ１３２および下りスロープ１３３を有する。ヘリウム濃度ピーク１４１は上りスロープ１４２および下りスロープ１４３を有する。第１のドナー濃度ピーク１１１は上りスロープ１１２および下りスロープ１１３を有する。第２のドナー濃度ピーク１２１は上りスロープ１２２および下りスロープ１２３を有する。空孔濃度ピーク１７１は上りスロープ１７２および下りスロープ１７３を有する。 Each concentration peak has an upward slope in which the concentration value increases and a downward slope in which the concentration value decreases from the lower surface 23 to the upper surface 21 of the semiconductor substrate 10. In this example, the hydrogen concentration peak 131 has an upslope 132 and a downslope 133. The helium concentration peak 141 has an upslope 142 and a downslope 143. The first donor concentration peak 111 has an upslope 112 and a downslope 113. The second donor concentration peak 121 has an upslope 122 and a downslope 123. The vacancy concentration peak 171 has an upslope 172 and a downslope 173.
　半導体基板１０のドナーには、水素イオンを注入する前から半導体基板１０に存在していたドナー、すなわちベースドーピング濃度（濃度Ｄｂ）と、注入された水素が活性化したドナーと、上述したＶＯＨ欠陥とが含まれる。水素がドナーとして活性化する比率は、例えば１％程度である。通過領域１０６のうち、第１の深さＺ１および第２の深さＺ２からある程度離れた領域では、水素化学濃度に対応するＶＯＨ欠陥によるドナーよりも、空孔欠陥濃度に対応するＶＯＨ欠陥によるドナーの比率が高くなり、ドナー濃度は空孔欠陥の濃度に律速される。水素化学濃度に対応するＶＯＨ欠陥とは、空孔欠陥濃度よりも、水素化学濃度が支配的なＶＯＨ欠陥を指す。空孔欠陥濃度に対応するＶＯＨ欠陥とは、水素化学濃度よりも、空孔欠陥濃度が支配的なＶＯＨ欠陥を指す。 For the donor of the semiconductor substrate 10, the donor existing in the semiconductor substrate 10 before the implantation of hydrogen ions, that is, the base doping concentration (concentration Db), the donor in which the implanted hydrogen is activated, and the VOH defect described above. And are included. The rate at which hydrogen is activated as a donor is, for example, about 1%. In the region of the passage region 106, which is apart from the first depth Z1 and the second depth Z2 to some extent, the donor by the VOH defect corresponding to the vacancy defect concentration is more than the donor by the VOH defect corresponding to the hydrogen chemical concentration. , The donor concentration is rate-limited by the concentration of vacancy defects. The VOH defect corresponding to the hydrogen chemical concentration refers to a VOH defect in which the hydrogen chemical concentration is more dominant than the vacancy defect concentration. The VOH defect corresponding to the vacancy defect concentration refers to a VOH defect in which the vacancy defect concentration is more dominant than the hydrogen chemical concentration.
　ここで、水素化学濃度分布が支配的なＶＯＨ欠陥とは、下記の意味とする。空孔、酸素、水素がクラスターを形成してＶＯＨ欠陥を形成する場合において、空孔欠陥濃度に対して水素化学濃度が十分多いために、ＶＯＨ欠陥によるドナー濃度の分布が、水素化学濃度の分布に相似であることを示す。一例として、ある深さおよびその近傍の深さにおいて、空孔欠陥濃度よりも水素化学濃度が大きい場合に、水素化学濃度分布が支配的なＶＯＨ欠陥のドナー濃度分布になると言える。 Here, the VOH defects in which the hydrogen chemical concentration distribution is dominant have the following meanings. In the case where vacancies, oxygen, and hydrogen form clusters to form VOH defects, since the hydrogen chemical concentration is sufficiently higher than the vacancy defect concentration, the distribution of the donor concentration due to the VOH defects is the distribution of the hydrogen chemical concentration. Is similar to. As an example, it can be said that when the hydrogen chemical concentration is higher than the vacancy defect concentration at a certain depth and in the vicinity thereof, the hydrogen chemical concentration distribution becomes the dominant VOH defect donor concentration distribution.
　一方、空孔欠陥濃度分布１７５が支配的なＶＯＨ欠陥とは、水素化学濃度に対して空孔欠陥濃度が十分多いために、ＶＯＨ欠陥によるドナー濃度の分布が、空孔欠陥濃度の分布に相似であることを示す。一例として、ある深さおよびその近傍の深さにおいて、水素化学濃度よりも空孔欠陥濃度が大きい場合に、空孔欠陥濃度分布１７５が支配的なＶＯＨ欠陥のドナー濃度分布になると言える。 On the other hand, a VOH defect in which the vacancy defect concentration distribution 175 is dominant means that the distribution of the donor concentration due to the VOH defect is similar to the distribution of the vacancy defect concentration because the vacancy defect concentration is sufficiently higher than the hydrogen chemical concentration. Is shown. As an example, it can be said that the vacancy defect concentration distribution 175 becomes the dominant VOH defect donor concentration distribution when the vacancy defect concentration is higher than the hydrogen chemical concentration at a certain depth and in the vicinity thereof.
　通過領域１０６には、第１の深さＺ１および第２の深さＺ２の近傍を除き、水素が通過することで生じた空孔（Ｖ、ＶＶ等）が、図２に示すように深さ方向にほぼ一様の濃度で分布すると考えられる。また、半導体基板１０の製造時等に注入される酸素（Ｏ）も、深さ方向に一様に分布すると考えられる。また、通過領域１０６には、水素濃度ピーク１３１の水素が拡散するので十分な量の水素が存在する。これらが、ＶＯＨ欠陥として、平坦なドナー分布を形成する。 In the passage region 106, except for the vicinity of the first depth Z1 and the second depth Z2, holes (V, VV, etc.) generated by passage of hydrogen have depths as shown in FIG. It is considered that the distribution is almost uniform in the direction. In addition, it is considered that oxygen (O) that is injected at the time of manufacturing the semiconductor substrate 10 is evenly distributed in the depth direction. In addition, since hydrogen of the hydrogen concentration peak 131 diffuses in the passage region 106, a sufficient amount of hydrogen exists. These form a flat donor distribution as VOH defects.
　このため、第１の深さＺ１および第２の深さＺ２の近傍以外の通過領域１０６には、ドナーとして機能するＶＯＨ欠陥がほぼ一様に分布した平坦領域１５０が存在する。平坦領域１５０におけるドナー濃度分布は、深さ方向においてほぼ一定である。ドナー濃度が深さ方向においてほぼ一定とは、例えば、ドナー濃度の最大値と最小値との差分がドナー濃度の最大値の５０％以内である領域が、深さ方向に連続している状態を指してよい。当該差分は、当該領域のドナー濃度の最大値の３０％以下であってよく、１０％以下であってもよい。 Therefore, in the passage region 106 other than the vicinity of the first depth Z1 and the second depth Z2, there is a flat region 150 in which VOH defects functioning as donors are distributed almost uniformly. The donor concentration distribution in the flat region 150 is almost constant in the depth direction. The donor concentration being substantially constant in the depth direction means, for example, that a region where the difference between the maximum value and the minimum value of the donor concentration is within 50% of the maximum value of the donor concentration is continuous in the depth direction. You can point. The difference may be 30% or less of the maximum value of the donor concentration of the region, and may be 10% or less.
　あるいは、深さ方向の所定範囲におけるドナー濃度分布の平均濃度に対して、ドナー濃度分布の値が、当該ドナー濃度分布の平均濃度の±５０％以内にあってよく、±３０％以内にあってよく、±１０％以内にあってよい。深さ方向の所定範囲は、一例として以下の通りでよい。つまり、第１の深さＺ１から第２の深さＺ２までの長さをＺＬとして、Ｚ１とＺ２との間の中心Ｚｃから、第１の深さＺ１側および第２の深さＺ２側にそれぞれ０．２５Ｚ離れた２点間の長さ０．５ＺＬの区間を当該範囲としてよい。平坦領域１５０の長さに応じて、所定範囲の長さを０．７５ＺＬとしてもよく、０．３ＺＬとしてもよく、０．９ＺＬとしてもよい。 Alternatively, the value of the donor concentration distribution may be within ±50% of the average concentration of the donor concentration distribution in a predetermined range in the depth direction, or within ±30% of the average concentration of the donor concentration distribution. Well, it may be within ±10%. The predetermined range in the depth direction may be as follows as an example. That is, assuming that the length from the first depth Z1 to the second depth Z2 is Z L , from the center Zc between Z1 and Z2, the first depth Z1 side and the second depth Z2 side Further, a section having a length of 0.5Z L between two points separated by 0.25Z may be set as the range. Depending on the length of the flat region 150, the length of the predetermined range may be a 0.75Z L, may be a 0.3Z L, it may be 0.9Z L.
　平坦領域１５０が設けられる範囲は、ヘリウム濃度ピーク１４１の位置により制御できる。平坦領域１５０は、水素濃度ピーク１３１と、ヘリウム濃度ピーク１４１との間に設けられる。また、平坦領域１５０のドナー濃度は、ヘリウム濃度ピーク１４１におけるヘリウムイオンのドーズ量で制御できる。ヘリウムイオンのドーズ量を多くすることで、通過領域１０６に生じる空孔（Ｖ）が多くなり、ドナー濃度が上昇する。 The range in which the flat region 150 is provided can be controlled by the position of the helium concentration peak 141. The flat region 150 is provided between the hydrogen concentration peak 131 and the helium concentration peak 141. Further, the donor concentration of the flat region 150 can be controlled by the dose amount of helium ions at the helium concentration peak 141. By increasing the dose amount of helium ions, the number of vacancies (V) generated in the passage region 106 increases and the donor concentration increases.
　なお、水素濃度ピーク１３１よりも深い位置にヘリウムイオンを注入するにあたり、ヘリウムイオンの加速エネルギーを、ヘリウムイオンが半導体基板１０を突き抜ける（貫通する）程度の値まで高くしてもよい。つまり、ヘリウム濃度ピーク１４１が半導体基板１０に残留しないようにしてもよい。これにより、空孔欠陥の濃度を増加させることも可能である。一方で、加速エネルギーが過大の場合、イオン注入時に基板が受けるダメージが強すぎて、通過領域１０６の空孔欠陥の分布に平坦性が保てなくなる場合がある。そのため、ヘリウム濃度ピーク１４１が半導体基板１０の内部に位置するようにしてよい。 When implanting helium ions at a position deeper than the hydrogen concentration peak 131, the acceleration energy of the helium ions may be increased to a value at which the helium ions penetrate (penetrate) the semiconductor substrate 10. That is, the helium concentration peak 141 may not be left on the semiconductor substrate 10. Thereby, it is possible to increase the concentration of vacancy defects. On the other hand, if the acceleration energy is excessively large, the substrate may be damaged too much during the ion implantation, and the flatness may not be maintained in the distribution of the vacancy defects in the passage region 106. Therefore, the helium concentration peak 141 may be located inside the semiconductor substrate 10.
　ヘリウム濃度ピーク１４１は、水素濃度ピーク１３１よりも深い位置に設けられるので、ピークの広がり方が、水素濃度ピーク１３１よりも大きくなりやすい。このため、第２のドナー濃度ピーク１２１も、第１のドナー濃度ピーク１１１に比べて、ピークの広がり方が大きくなりやすい。つまり、第２のドナー濃度ピーク１２１は、第１のドナー濃度ピーク１１１よりもなだらかなピークになりやすい。 Since the helium concentration peak 141 is provided at a position deeper than the hydrogen concentration peak 131, the spread of the peak tends to be larger than that of the hydrogen concentration peak 131. For this reason, the second donor concentration peak 121 also tends to have a larger peak spread than the first donor concentration peak 111. That is, the second donor concentration peak 121 tends to be a gentler peak than the first donor concentration peak 111.
　また本例では、水素濃度ピーク１３１の濃度値が、ヘリウム濃度ピーク１４１の濃度値よりも大きい。水素濃度ピーク１３１の濃度値が、ヘリウム濃度ピーク１４１の濃度値の１０倍以上であってよく、１００倍以上であってもよい。他の例では、水素濃度ピーク１３１の濃度値が、ヘリウム濃度ピーク１４１の濃度値以下であってもよい。 Further, in this example, the concentration value of the hydrogen concentration peak 131 is larger than the concentration value of the helium concentration peak 141. The concentration value of the hydrogen concentration peak 131 may be 10 times or more the concentration value of the helium concentration peak 141, or may be 100 times or more. In another example, the concentration value of the hydrogen concentration peak 131 may be equal to or lower than the concentration value of the helium concentration peak 141.
　本例では、水素濃度ピーク１３１の濃度値が高いので、水素濃度ピーク１３１においてドナーとして活性化する水素の量も比較的に多くなる。つまり、空孔欠陥濃度分布１７５に対して、水素化学濃度分布が支配的なＶＯＨ欠陥のドナーの比率が高くなる。この場合、第１のドナー濃度ピーク１１１の形状は、水素濃度ピーク１３１の形状と相似する。 In this example, since the concentration value of the hydrogen concentration peak 131 is high, the amount of hydrogen activated as a donor in the hydrogen concentration peak 131 is relatively large. In other words, the ratio of donors of VOH defects whose hydrogen chemical concentration distribution is dominant is higher than that of the vacancy defect concentration distribution 175. In this case, the shape of the first donor concentration peak 111 is similar to the shape of the hydrogen concentration peak 131.
　一方で、ヘリウム濃度ピーク１４１は水素濃度ピーク１３１から離れているので、ヘリウム濃度ピーク１４１においてドナーとして活性化する水素の量は少ない。つまり、水素化学濃度分布が支配的なＶＯＨ欠陥のドナーに比べて、空孔欠陥濃度分布１７５が支配的なＶＯＨ欠陥のドナーの比率が比較的に高くなる。この場合、第２のドナー濃度ピーク１２１の形状と、ヘリウム濃度ピーク１４１の形状との相似度は、第１のドナー濃度ピーク１１１の形状と水素濃度ピーク１３１の形状との相似度よりも小さくなる。ＶＯＨ欠陥は、通過領域１０６のほとんどにおいてほぼ一様に分布すると考えられるので、第２のドナー濃度ピーク１２１は、更になだらかな形状になる。ピーク形状の相似度は、水素濃度ピークまたはヘリウム濃度ピークと、ドナー濃度ピークとの間で、対応するスロープの傾きの差が大きくなるほど小さい値を示す指標であってよい。 On the other hand, since the helium concentration peak 141 is apart from the hydrogen concentration peak 131, the amount of hydrogen activated as a donor at the helium concentration peak 141 is small. That is, the ratio of VOH defect donors in which the vacancy defect concentration distribution 175 is dominant is relatively higher than that of VOH defect donors in which the hydrogen chemical concentration distribution is dominant. In this case, the similarity between the shape of the second donor concentration peak 121 and the shape of the helium concentration peak 141 is smaller than the similarity between the shape of the first donor concentration peak 111 and the shape of the hydrogen concentration peak 131. .. Since it is considered that the VOH defects are distributed almost uniformly in most of the passage region 106, the second donor concentration peak 121 has a more gentle shape. The similarity of the peak shapes may be an index showing a smaller value as the difference in slope of the corresponding slope between the hydrogen concentration peak or the helium concentration peak and the donor concentration peak increases.
　このような構造により、第１の深さＺ１と、第２の深さＺ２との間に、平坦領域１５０を設けることができる。平坦領域１５０の深さ方向における長さは、半導体基板１０の深さ方向における厚みの１０％以上であってよく、３０％以上であってよく、５０％以上であってもよい。また、平坦領域１５０の深さ方向における長さは、１０μｍ以上であってよく、３０μｍ以上であってよく、５０μｍ以上であってよく、１００μｍ以上であってもよい。 With such a structure, the flat region 150 can be provided between the first depth Z1 and the second depth Z2. The length of the flat region 150 in the depth direction may be 10% or more, 30% or more, and 50% or more of the thickness of the semiconductor substrate 10 in the depth direction. The length of the flat region 150 in the depth direction may be 10 μm or more, 30 μm or more, 50 μm or more, and 100 μm or more.
　平坦領域１５０のドナー濃度の最小値は、半導体基板１０のベースドーピング濃度Ｄｂより高くてよい。つまり、平坦領域１５０のドナー濃度は、平坦領域１５０の全体にわたって、ベースドーピング濃度Ｄｂより高くてよい。平坦領域１５０のドナー濃度と、半導体基板１０のベースドーピング濃度Ｄｂとの差分は、例えばヘリウム濃度ピーク１４１におけるヘリウムドーズ量で調整できる。 The minimum donor concentration of the flat region 150 may be higher than the base doping concentration Db of the semiconductor substrate 10. That is, the donor concentration of the flat region 150 may be higher than the base doping concentration Db over the entire flat region 150. The difference between the donor concentration of the flat region 150 and the base doping concentration Db of the semiconductor substrate 10 can be adjusted by the helium dose amount at the helium concentration peak 141, for example.
　第１の深さＺ１と第２の深さＺ２との間におけるドナー濃度の最小値は、半導体基板１０のベースドーピング濃度より高くてもよい。水素濃度ピーク１３１と、ヘリウム濃度ピーク１４１との間は、Ｎ型の領域が連続して設けられていてよい。また、第２の深さＺ２と、半導体基板１０の下面２３との間におけるドナー濃度の最小値は、半導体基板１０のドナー濃度より高くてもよい。 The minimum value of the donor concentration between the first depth Z1 and the second depth Z2 may be higher than the base doping concentration of the semiconductor substrate 10. An N-type region may be continuously provided between the hydrogen concentration peak 131 and the helium concentration peak 141. Further, the minimum value of the donor concentration between the second depth Z2 and the lower surface 23 of the semiconductor substrate 10 may be higher than the donor concentration of the semiconductor substrate 10.
　図３Ａは、水素濃度ピーク１３１と、第１のドナー濃度ピーク１１１との関係を説明する図である。本例では、水素濃度ピーク１３１の上りスロープ１３２の傾き１３４を用いて、第１のドナー濃度ピーク１１１の上りスロープ１１２の傾き１１４を規格化する。規格化は、一例として傾き１３４で傾き１１４を除算する処理である。なお、本明細書において、傾きは、傾きの絶対値という意味で使用される場合がある。 FIG. 3A is a diagram illustrating the relationship between the hydrogen concentration peak 131 and the first donor concentration peak 111. In this example, the slope 134 of the upward slope 132 of the hydrogen concentration peak 131 is used to normalize the slope 114 of the upward slope 112 of the first donor concentration peak 111. The normalization is a process of dividing the slope 114 by the slope 134 as an example. In this specification, the inclination may be used to mean the absolute value of the inclination.
　上りスロープの傾きは、濃度が極大値を示す位置と、濃度が極大値に対して予め定められた比率となる位置との傾きであってよい。予め定められた比率は、８０％であってよく、５０％であってよく、１０％であってよく、１％であってよく、他の比率を用いてもよい。また、水素濃度ピーク１３１および第１のドナー濃度ピーク１１１においては、第１の深さＺ１と、半導体基板１０の下面２３との間の濃度分布の傾きを用いてもよい。図３Ａに示す例では、水素濃度ピーク１３１の傾き１３４は（Ｈ１－ａＨ１）／（Ｚ１－Ｚ３）で与えられ、第１のドナー濃度ピーク１１１の傾き１１４は（Ｄ１－ａＤ１）／（Ｚ１－Ｚ４）で与えられる。Ｈ１は第１の深さＺ１における水素濃度であり、Ｄ１は第１の深さＺ１におけるドナー濃度であり、ａは予め定められた比率であり、Ｚ３は水素濃度ピーク１３１の上りスロープ１３２において水素濃度がａＨ１となる深さであり、Ｚ４は第１のドナー濃度ピーク１１１の上りスロープ１１２においてドナー濃度がａＤ１となる深さである。例えば、傾き１３４で傾き１１４を規格化すると、（Ｄ１－ａＤ１）（Ｚ１－Ｚ３）／｛（Ｈ１－ａＨ１）（Ｚ１－Ｚ４）｝となる。傾き１３４で傾き１１４を規格化した傾きをαとする。 The slope of the ascending slope may be the slope between the position where the concentration has a maximum value and the position where the concentration has a predetermined ratio with respect to the maximum value. The predetermined ratio may be 80%, 50%, 10%, 1% and other ratios may be used. In the hydrogen concentration peak 131 and the first donor concentration peak 111, the slope of the concentration distribution between the first depth Z1 and the lower surface 23 of the semiconductor substrate 10 may be used. In the example shown in FIG. 3A, the slope 134 of the hydrogen concentration peak 131 is given by (H1-aH1)/(Z1-Z3), and the slope 114 of the first donor concentration peak 111 is (D1-aD1)/(Z1- Z4) is given. H1 is the hydrogen concentration at the first depth Z1, D1 is the donor concentration at the first depth Z1, a is a predetermined ratio, and Z3 is hydrogen at the up slope 132 of the hydrogen concentration peak 131. The concentration is a depth at which the donor concentration is aH1, and Z4 is the depth at which the donor concentration is aD1 in the upslope 112 of the first donor concentration peak 111. For example, when the slope 114 is standardized by the slope 134, it becomes (D1-aD1)(Z1-Z3)/{(H1-aH1)(Z1-Z4)}. The inclination obtained by normalizing the inclination 114 with the inclination 134 is α.
　図３Ｂは、ヘリウム濃度ピーク１４１と、第２のドナー濃度ピーク１２１との関係を説明する図である。本例では、ヘリウム濃度ピーク１４１の上りスロープ１４２の傾き１４４を用いて、第２のドナー濃度ピーク１２１の上りスロープ１２２の傾き１２４を規格化する。 FIG. 3B is a diagram illustrating the relationship between the helium concentration peak 141 and the second donor concentration peak 121. In this example, the slope 144 of the upward slope 142 of the helium concentration peak 141 is used to standardize the slope 124 of the upward slope 122 of the second donor concentration peak 121.
　図３Ｂに示す例では、ヘリウム濃度ピーク１４１の傾き１４４は（Ｈ２－ａＨ２）／（Ｚ２－Ｚ５）で与えられ、第２のドナー濃度ピーク１２１の傾き１２４は（Ｄ２－ａＤ２）／（Ｚ２－Ｚ６）で与えられる。Ｈ２は第２の深さＺ２におけるヘリウム濃度であり、Ｄ２は第２の深さＺ２におけるドナー濃度であり、ａは予め定められた比率であり、Ｚ５はヘリウム濃度ピーク１４１の上りスロープ１４２においてヘリウム濃度がａＨ２となる深さであり、Ｚ６は第２のドナー濃度ピーク１２１の上りスロープ１２２においてドナー濃度がａＤ２となる深さである。第２のドナー濃度ピーク１２１の傾きを規格化するのに用いる比率ａは、第１のドナー濃度ピーク１１１の傾きを規格化するのに用いる比率ａと同一であってよく、異なっていてもよい。例えば、傾き１４４で傾き１２４を規格化すると、（Ｄ２－ａＤ２）（Ｚ２－Ｚ５）／｛（Ｚ２－Ｚ６）（Ｈ２－ａＨ２）｝となる。傾き１４４で傾き１２４を規格化した傾きをβとする。 In the example shown in FIG. 3B, the slope 144 of the helium concentration peak 141 is given by (H2-aH2)/(Z2-Z5), and the slope 124 of the second donor concentration peak 121 is (D2-aD2)/(Z2- Z6). H2 is the helium concentration at the second depth Z2, D2 is the donor concentration at the second depth Z2, a is a predetermined ratio, and Z5 is helium at the upward slope 142 of the helium concentration peak 141. The concentration is a depth at which the donor concentration becomes aH2, and Z6 is the depth at which the donor concentration becomes aD2 in the upward slope 122 of the second donor concentration peak 121. The ratio a used to normalize the slope of the second donor concentration peak 121 may be the same as or different from the ratio a used to normalize the slope of the first donor concentration peak 111. .. For example, when the slope 124 is standardized by the slope 144, it becomes (D2-aD2)(Z2-Z5)/{(Z2-Z6)(H2-aH2)}. Let β be the slope obtained by normalizing the slope 124 with the slope 144.
　第２のドナー濃度ピーク１２１の上りスロープ１２２の規格化された傾きβは、第１のドナー濃度ピーク１１１の上りスロープ１１２の規格化された傾きαよりも小さい。つまり、第２のドナー濃度ピーク１２１のほうが、第１のドナー濃度ピーク１１１に比べて、水素またはヘリウムの濃度ピークに対してよりなだらかなピークになっている。このような第２のドナー濃度ピーク１２１が形成されるように水素イオンおよびヘリウムイオンを注入することで、平坦領域１５０を形成できる。また、第２のドナー濃度ピーク１２１をなだらかな形状にすることで、平坦領域１５０の先端におけるドナー濃度の変化を緩やかにすることもできる。第２のドナー濃度ピーク１２１の上りスロープ１２２の規格化された傾きβは、第１のドナー濃度ピーク１１１の上りスロープ１１２の規格化された傾きαの１倍以下であってよく、０．１倍以下であってよく、０．０１倍以下であってもよい。 The standardized slope β of the upward slope 122 of the second donor concentration peak 121 is smaller than the standardized slope α of the upward slope 112 of the first donor concentration peak 111. That is, the second donor concentration peak 121 is a gentler peak with respect to the concentration peak of hydrogen or helium than the first donor concentration peak 111. The flat region 150 can be formed by implanting hydrogen ions and helium ions so that the second donor concentration peak 121 is formed. Further, by making the second donor concentration peak 121 have a gentle shape, it is possible to moderate the change in the donor concentration at the tip of the flat region 150. The normalized slope β of the upslope 122 of the second donor concentration peak 121 may be less than or equal to 1 times the normalized slope α of the upslope 112 of the first donor concentration peak 111, 0.1 It may be less than or equal to double, or less than or equal to 0.01.
　また、ヘリウム濃度ピーク１４１の上りスロープ１４２の傾き１４４は、下りスロープ１４３の傾き１４５よりも小さくてよい。下面２３から深い位置に注入したヘリウムイオンの濃度分布は、下面２３側にゆるやかな裾を引く場合があるので、上りスロープ１４２の傾き１４４と、下りスロープ１４３の傾き１４５とを比較することで、ヘリウム濃度ピーク１４１のヘリウムが、下面２３側から注入されたか否かを判別できる場合がある。傾き１４５は（Ｈ２－ａＨ２）／（Ｚ７－Ｚ２）で与えられる。傾き１２５は（Ｄ２－ａＤ２）／（Ｚ７－Ｚ２）で与えられる。なお、図３Ｂにおいては、第２のドナー濃度ピーク１２１の上りスロープ１２２の傾き１２４が、下りスロープ１２３の傾き１２５より大きいが、ヘリウム濃度ピーク１４１と同様に、第２のドナー濃度ピーク１２１の上りスロープ１２２の傾き１２４は、下りスロープ１２３の傾き１２５より小さくてもよい。 The slope 144 of the upward slope 142 of the helium concentration peak 141 may be smaller than the slope 145 of the downward slope 143. Since the concentration distribution of the helium ions implanted at a deep position from the lower surface 23 may have a gentle skirt on the lower surface 23 side, by comparing the slope 144 of the ascending slope 142 and the slope 145 of the descending slope 143, It may be possible to determine whether or not the helium of the helium concentration peak 141 is injected from the lower surface 23 side. The slope 145 is given by (H2-aH2)/(Z7-Z2). The slope 125 is given by (D2-aD2)/(Z7-Z2). Note that in FIG. 3B, the slope 124 of the upward slope 122 of the second donor concentration peak 121 is larger than the slope 125 of the downward slope 123, but like the helium concentration peak 141, the upward slope of the second donor concentration peak 121. The slope 124 of the slope 122 may be smaller than the slope 125 of the down slope 123.
　図３Ｃは、上りスロープ１４２の傾きを説明する図である。上りスロープ１４２の傾きは、以下のように考えてもよい。図３Ｃに記載しているように、ヘリウム濃度ピーク１４１において、ピーク濃度Ｈ２の１０％（０．１×Ｈ２）の濃度となる２つの位置Ｚ８、Ｚ９の間の幅（１０％全幅）を、ＦＷ１０％Ｍとする。２つの位置Ｚ８、Ｚ９は、ピーク位置Ｚ２を挟んで、ヘリウム濃度が０．１×Ｈ２となる点のうち、ピーク位置Ｚ２に最も近い２つの位置である。２つの位置Ｚ８、Ｚ９のうち水素濃度ピーク側の位置をＺ８とする。位置Ｚ８におけるドナー濃度の傾きはほぼ平坦である。位置Ｚ８におけるヘリウム濃度の傾きは、位置Ｚ８におけるドナー濃度の傾きの１００倍を超える。例えば、位置Ｚ８におけるヘリウム濃度の傾きは位置Ｚ８におけるドナー濃度の傾きの１００倍以上であってよく、１０００倍以上であってよい。 FIG. 3C is a diagram illustrating the slope of the uphill slope 142. The slope of the ascending slope 142 may be considered as follows. As shown in FIG. 3C, in the helium concentration peak 141, the width (10% full width) between the two positions Z8 and Z9 at which the concentration becomes 10% (0.1×H2) of the peak concentration H2, FW 10%M. The two positions Z8 and Z9 are the two positions closest to the peak position Z2 among the points where the helium concentration is 0.1×H2 with the peak position Z2 sandwiched therebetween. The position on the hydrogen concentration peak side of the two positions Z8 and Z9 is Z8. The slope of the donor concentration at the position Z8 is almost flat. The slope of the helium concentration at the position Z8 exceeds 100 times the slope of the donor concentration at the position Z8. For example, the slope of the helium concentration at the position Z8 may be 100 times or more the slope of the donor concentration at the position Z8, and may be 1000 times or more.
　図４Ａは、上りスロープ１１２の傾きの規格化の他の定義を説明する図である。上りスロープ１１２の傾きの規格化においては、例えば、以下の指標γを導入する。図３Ａの例では位置Ｚ３と位置Ｚ４とが異なっていたが、本例では位置Ｚ３と位置Ｚ４を同じ位置とする（Ｚ３＝Ｚ４）。位置Ｚ３は、ここでは予め定められた位置である。位置Ｚ３は、水素濃度分布およびドナー濃度分布が、位置Ｚ１よりも下面側にて上りスロープ１３２、１１２となっている位置であればよい。位置Ｚ３における水素濃度をａ×Ｈ１、ドナー濃度をｂ×Ｄ１とする。ａは位置Ｚ１の水素濃度ピーク１３１の濃度Ｈ１に対する、位置Ｚ３における水素濃度の比率である。ｂは位置Ｚ１の第１のドナー濃度ピーク１１１の濃度Ｄ１に対する、位置Ｚ３のドナー濃度の比率である。ここで、区間Ｚ３～Ｚ１における水素濃度およびドナー濃度のそれぞれ傾きの比と、当該傾きの比を規格化した傾き比γを導入する。区間Ｚ３～Ｚ１における水素濃度の傾きの比を、（Ｈ１／ａＨ１）／（Ｚ１－Ｚ３）と定義する。同じく、区間Ｚ３～Ｚ１におけるドナー濃度の傾きの比を、（Ｄ１／ｂＤ１）／（Ｚ１－Ｚ３）と定義する。そして、区間Ｚ３～Ｚ１における水素濃度の傾きの比で、ドナー濃度の傾きの比を規格化した傾き比γを、｛（Ｄ１／ｂＤ１）／（Ｚ１－Ｚ３）｝／｛（Ｈ１／ａＨ１）／（Ｚ１－Ｚ３）｝と定義する。規格化した傾き比γは、前式を計算することにより、簡単な比ａ／ｂとなる。 FIG. 4A is a diagram illustrating another definition of standardization of the slope of the upslope 112. In normalizing the slope of the upslope 112, for example, the following index γ is introduced. In the example of FIG. 3A, the position Z3 and the position Z4 are different, but in this example, the position Z3 and the position Z4 are the same position (Z3=Z4). The position Z3 is a predetermined position here. The position Z3 may be a position where the hydrogen concentration distribution and the donor concentration distribution have the upward slopes 132 and 112 on the lower surface side with respect to the position Z1. The hydrogen concentration at position Z3 is a×H1, and the donor concentration is b×D1. a is the ratio of the hydrogen concentration at the position Z3 to the concentration H1 of the hydrogen concentration peak 131 at the position Z1. b is the ratio of the donor concentration at the position Z3 to the concentration D1 of the first donor concentration peak 111 at the position Z1. Here, the ratio of the slopes of the hydrogen concentration and the donor concentration in the sections Z3 to Z1 and the slope ratio γ that normalizes the ratio of the slopes are introduced. The ratio of the slope of the hydrogen concentration in the section Z3 to Z1 is defined as (H1/aH1)/(Z1-Z3). Similarly, the ratio of the gradient of the donor concentration in the sections Z3 to Z1 is defined as (D1/bD1)/(Z1-Z3). Then, the gradient ratio γ obtained by normalizing the gradient ratio of the donor concentration by the gradient ratio of the hydrogen concentration in the sections Z3 to Z1 is {(D1/bD1)/(Z1-Z3)}/{(H1/aH1) /(Z1-Z3)}. The normalized slope ratio γ becomes a simple ratio a/b by calculating the above equation.
　図４Ｂは、上りスロープ１２２の傾きの規格化の他の定義を説明する図である。上りスロープ１２２の傾きの規格化においては、例えば、指標γと同様の指標εを導入する。図３Ｂの例では位置Ｚ５と位置Ｚ６とが異なっていたが、本例では位置Ｚ５と位置Ｚ６を同じ位置とする（Ｚ５＝Ｚ６）。位置Ｚ５は、ここでは予め定められた位置である。位置Ｚ５は、ヘリウム濃度分布およびドナー濃度分布が、位置Ｚ２よりも下面側にて上りスロープ１４２、１２２となっている位置であればよい。位置Ｚ５におけるヘリウム濃度をｃ×Ｈ２、ドナー濃度をｄ×Ｄ２とする。ｃは位置Ｚ２のヘリウム濃度ピーク１４１の濃度Ｈ２に対する、位置Ｚ５におけるヘリウム濃度の比率である。ｄは位置Ｚ１の第２のドナー濃度ピーク１２１の濃度Ｄ２に対する、位置Ｚ５のドナー濃度の比率である。ここで、区間Ｚ５～Ｚ２におけるヘリウム濃度およびドナー濃度のそれぞれ傾きの比と、当該傾きの比を規格化した傾き比εを導入する。区間Ｚ５～Ｚ２におけるヘリウム濃度の傾きの比を、（Ｈ２／ｃＨ２）／（Ｚ２－Ｚ５）と定義する。同じく、区間Ｚ５～Ｚ２におけるドナー濃度の傾きの比を、（Ｄ２／ｄＤ２）／（Ｚ２－Ｚ５）と定義する。そして、区間Ｚ５～Ｚ２におけるヘリウム濃度の傾きの比で、ドナー濃度の傾きの比を規格化した傾き比εを、｛（Ｄ２／ｄＤ２）／（Ｚ２－Ｚ５）｝／｛（Ｈ２／ｃＨ２）／（Ｚ２－Ｚ５）｝と定義する。規格化した傾き比εは、前式を計算することにより、簡単な比ｃ／ｄとなる。 FIG. 4B is a diagram illustrating another definition of standardization of the slope of the upslope 122. In normalizing the slope of the upslope 122, for example, an index ε similar to the index γ is introduced. In the example of FIG. 3B, the position Z5 and the position Z6 are different, but in this example, the position Z5 and the position Z6 are the same position (Z5=Z6). The position Z5 is a predetermined position here. The position Z5 may be a position where the helium concentration distribution and the donor concentration distribution are the up slopes 142 and 122 on the lower surface side of the position Z2. The helium concentration at the position Z5 is c×H2, and the donor concentration is d×D2. c is the ratio of the helium concentration at position Z5 to the concentration H2 of the helium concentration peak 141 at position Z2. d is the ratio of the donor concentration at the position Z5 to the concentration D2 of the second donor concentration peak 121 at the position Z1. Here, the ratio of the slopes of the helium concentration and the donor concentration in the sections Z5 to Z2 and the slope ratio ε obtained by normalizing the ratio of the slopes are introduced. The ratio of the helium concentration gradients in the sections Z5 to Z2 is defined as (H2/cH2)/(Z2-Z5). Similarly, the ratio of the gradients of the donor concentrations in the sections Z5 to Z2 is defined as (D2/dD2)/(Z2-Z5). Then, the slope ratio ε obtained by normalizing the slope ratio of the donor concentration by the slope ratio of the helium concentration in the sections Z5 to Z2 is {(D2/dD2)/(Z2-Z5)}/{(H2/cH2) /(Z2-Z5)}. The normalized slope ratio ε becomes a simple ratio c/d by calculating the above equation.
　水素濃度ピーク１３１と第１のドナー濃度ピーク１１１については、水素濃度分布とドナー濃度分布は相似形になることが多い。ここで相似形になるとは、例えば横軸を深さ、縦軸を濃度の常用対数としたときに、ドナー濃度分布は水素濃度分布を反映した分布を示すことを意味する。すなわち、所定の区間Ｚ３～Ｚ１において、水素イオンをイオン注入し、さらに熱アニールを行うことにより、ドナー濃度分布は水素濃度分布を反映した分布となる。一例として、水素濃度ピーク１３１のＨ１が１×１０１７ａｔоｍｓ／ｃｍ３で、位置Ｚ３の水素濃度ａＨ１が２×１０１６ａｔоｍｓ／ｃｍ３とすると、ａは０．２となる。一方、第１のドナー濃度ピーク１１１のＤ１が１×１０１６ａｔоｍｓ／ｃｍ３で、位置Ｚ３のドナー濃度ｂＤ１が２×１０１５ａｔоｍｓ／ｃｍ３とすると、ｂは０．２となる。したがって、規格化した傾き比γは、ａ／ｂであるので、１となる。すなわち、下面に近い深さ位置Ｚ１においては、水素濃度分布の傾きの比ａとドナー濃度分布の傾きの比ｂはほぼ同じ値となり、相似形であると言える。 Regarding the hydrogen concentration peak 131 and the first donor concentration peak 111, the hydrogen concentration distribution and the donor concentration distribution often have similar shapes. Here, having a similar shape means that the donor concentration distribution shows a distribution that reflects the hydrogen concentration distribution, where the horizontal axis is the depth and the vertical axis is the common logarithm of the concentration. That is, in the predetermined section Z3 to Z1, by implanting hydrogen ions and further performing thermal annealing, the donor concentration distribution becomes a distribution that reflects the hydrogen concentration distribution. As an example, if H1 of the hydrogen concentration peak 131 is 1×10 17 atms/cm 3 and the hydrogen concentration aH1 at the position Z3 is 2×10 16 atms/cm 3 , a is 0.2. On the other hand, when D1 of the first donor concentration peak 111 is 1×10 16 atms/cm 3 and the donor concentration bD1 at the position Z3 is 2×10 15 atms/cm 3 , b becomes 0.2. Therefore, the normalized slope ratio γ is a/b and thus becomes 1. That is, at the depth position Z1 close to the lower surface, the slope ratio a of the hydrogen concentration distribution and the slope ratio b of the donor concentration distribution have almost the same value, and it can be said that they have a similar shape.
　一方、ヘリウム濃度ピーク１４１と第２のドナー濃度ピーク１２１については、ヘリウム濃度分布とドナー濃度分布は相似形にならなくてもよい。すなわち、所定の区間Ｚ５～Ｚ２において、ドナー濃度分布はヘリウム濃度分布を反映しなくてもよい。一例として、ヘリウム濃度ピーク１４１のＨ２が１×１０１６ａｔоｍｓ／ｃｍ３で、位置Ｚ５のヘリウム濃度ｃＨ２が１×１０１５ａｔоｍｓ／ｃｍ３とすると、ｃは０．１となる。一方、第２のドナー濃度ピーク１２１のＤ２が３×１０１４ａｔоｍｓ／ｃｍ３で、位置Ｚ５のドナー濃度ｄＤ２が１．５×１０１４ａｔоｍｓ／ｃｍ３とすると、ｄは０．５となる。したがって、規格化した傾き比εは、ｃ／ｄであるので、０．２となる。すなわち、下面から十分深い位置深さ位置Ｚ２においては、ヘリウム濃度分布の傾きの比ｃはドナー濃度分布の傾きの比ｄよりも０．２倍の値となり、相似とは離れた形を示すと言える。 On the other hand, regarding the helium concentration peak 141 and the second donor concentration peak 121, the helium concentration distribution and the donor concentration distribution do not have to have similar shapes. That is, the donor concentration distribution does not have to reflect the helium concentration distribution in the predetermined sections Z5 to Z2. As an example, if H2 of the helium concentration peak 141 is 1×10 16 atms/cm 3 and helium concentration cH2 at the position Z5 is 1×10 15 atms/cm 3 , c is 0.1. On the other hand, if D2 of the second donor concentration peak 121 is 3×10 14 atms/cm 3 and the donor concentration dD2 at the position Z5 is 1.5×10 14 atms/cm 3 , d is 0.5. Therefore, the normalized inclination ratio ε is 0.2 because it is c/d. That is, at the position Z2 deep enough from the lower surface, the helium concentration distribution slope ratio c is 0.2 times the donor concentration distribution slope ratio d, indicating that the helium concentration distribution has a shape different from the similarity. I can say.
　規格化した傾き比γとεを比較すると、ヘリウム濃度分布のピーク位置が下面に近い場合にγは１に近くなり、ヘリウム濃度分布のピーク位置が下面から十分深い場合にはεは１よりも十分小さい値になってよい。すなわち、規格化した傾き比εは、規格化した傾き比γよりも小さくてよい。さらに、傾き比εは、０．９以下であってよく、０．５以下であってよく、０．２以下であってよい。あるいは、０．１以下であってよく、０．０１以下であってもよい。 Comparing the normalized slope ratios γ and ε, γ is close to 1 when the peak position of the helium concentration distribution is near the bottom surface, and ε is more than 1 when the peak position of the helium concentration distribution is sufficiently deep from the bottom surface. The value may be small enough. That is, the normalized slope ratio ε may be smaller than the normalized slope ratio γ. Further, the slope ratio ε may be 0.9 or less, 0.5 or less, and 0.2 or less. Alternatively, it may be 0.1 or less, or 0.01 or less.
　さらに、第２のドナー濃度ピーク１２１の他の例として、キャリア移動度の低下により、広がり抵抗から算出したドナー濃度、すなわちキャリア濃度が、深さ位置Ｚ２において前後の位置のキャリア濃度より低下する場合がある。このような場合は、上りスロープ１２２は減少の傾きとなるので、ｄは符号を負とする。つまりｄは絶対値が１以上の負の数となる。これにより、εは負の数となる。すなわち、規格化した傾き比εは規格化した傾き比γよりも小さくてよい。さらに、傾き比εは、０．９以下であってよく、０以下であってよく、－１以下であってもよい。あるいは、－１０以下であってよく、－１００以下であってよい。 Further, as another example of the second donor concentration peak 121, when the carrier mobility is lowered, the donor concentration calculated from the spreading resistance, that is, the carrier concentration is lower than the carrier concentrations at the front and rear positions at the depth position Z2. There is. In such a case, the ascending slope 122 has a decreasing slope, and therefore d has a negative sign. That is, d is a negative number whose absolute value is 1 or more. As a result, ε becomes a negative number. That is, the normalized slope ratio ε may be smaller than the normalized slope ratio γ. Further, the slope ratio ε may be 0.9 or less, 0 or less, or −1 or less. Alternatively, it may be −10 or less and −100 or less.
　なお、ヘリウム濃度ピーク１４１の実際の位置と、第２のドナー濃度ピーク１２１の実際の位置が、異なる場合もある。また、水素濃度ピーク１３１の位置と第１のドナー濃度ピーク１１１の位置も、厳密に一致しない場合もある。このように水素またはヘリウムの濃度ピークの位置と、ドナー濃度の位置とが一致しない場合は、ドナー濃度については、水素またはヘリウム濃度のピーク位置における濃度を便宜的にピークの位置としてもよい。これにより、上記の定義による計算は可能となる。 Note that the actual position of the helium concentration peak 141 and the actual position of the second donor concentration peak 121 may be different. In addition, the position of the hydrogen concentration peak 131 and the position of the first donor concentration peak 111 may not be exactly the same. When the position of the concentration peak of hydrogen or helium and the position of the donor concentration do not coincide with each other in this way, the concentration of the hydrogen or helium concentration at the peak position may be used as the peak position for convenience. This allows the calculation according to the above definition.
　以上の説明で重要な点は、ヘリウム濃度ピーク１４１は、極大値を備えることである。すなわち、ヘリウム濃度の分布が、深さＺ２において極大値を備えることである。ヘリウム濃度ピーク１４１が極大値を備えていることで、上記の規格化した傾き比の比較を可能としている。 The important point in the above explanation is that the helium concentration peak 141 has a maximum value. That is, the helium concentration distribution has a maximum value at the depth Z2. Since the helium concentration peak 141 has the maximum value, it is possible to compare the normalized slope ratios.
　図５は、平坦領域１５０を説明する図である。上述したように、平坦領域１５０におけるドナー濃度分布は、深さ方向においてほぼ一定である。平坦領域１５０は、ドナー濃度が、所定の最大値maxと所定の最小値minとの間となっている領域が、深さ方向において連続している部分である。最大値maxは、当該領域におけるドナー濃度の最大値を用いてよい。最小値minは、最大値maxの５０％の値であってよく、７０％の値であってよく、９０％の値であってもよい。 FIG. 5 is a diagram illustrating the flat area 150. As described above, the donor concentration distribution in the flat region 150 is almost constant in the depth direction. The flat region 150 is a region where the region where the donor concentration is between a predetermined maximum value max and a predetermined minimum value min is continuous in the depth direction. As the maximum value max, the maximum value of the donor concentration in the region may be used. The minimum value min may be a value of 50% of the maximum value max, a value of 70%, or a value of 90%.
　あるいは、前述のように、深さ方向の所定範囲におけるドナー濃度分布の平均濃度に対して、ドナー濃度分布の値が、当該ドナー濃度分布の平均濃度の±５０％以内にあってよく、±３０％以内にあってよく、±１０％以内にあってよい。深さ方向の所定範囲も、前述と同じであってよい。 Alternatively, as described above, the value of the donor concentration distribution may be within ±50% of the average concentration of the donor concentration distribution with respect to the average concentration of the donor concentration distribution in a predetermined range in the depth direction, and ±30%. %, and ±10%. The predetermined range in the depth direction may be the same as described above.
　図６は、半導体装置１００の構造例を示す図である。本例の半導体装置１００は、ＩＧＢＴとして機能する。本例の半導体装置１００は、半導体基板１０、層間絶縁膜３８、エミッタ電極５２およびコレクタ電極５４を有する。層間絶縁膜３８は、半導体基板１０の上面２１のすくなくとも一部を覆って形成される。層間絶縁膜３８には、コンタクトホール等の貫通孔が形成されている。コンタクトホールにより、半導体基板１０の上面２１が露出する。層間絶縁膜３８は、ＰＳＧ、ＢＰＳＧ等のシリケートガラスであってよく、酸化膜または窒化膜等であってもよい。 FIG. 6 is a diagram showing a structural example of the semiconductor device 100. The semiconductor device 100 of this example functions as an IGBT. The semiconductor device 100 of this example has a semiconductor substrate 10, an interlayer insulating film 38, an emitter electrode 52, and a collector electrode 54. The interlayer insulating film 38 is formed so as to cover at least a part of the upper surface 21 of the semiconductor substrate 10. Through holes such as contact holes are formed in the interlayer insulating film 38. The upper surface 21 of the semiconductor substrate 10 is exposed by the contact hole. The interlayer insulating film 38 may be silicate glass such as PSG and BPSG, and may be an oxide film or a nitride film.
　エミッタ電極５２は、半導体基板１０および層間絶縁膜３８の上面に形成される。エミッタ電極５２は、コンタクトホールの内部にも形成されており、コンタクトホールにより露出する半導体基板１０の上面２１と接触している。 The emitter electrode 52 is formed on the upper surfaces of the semiconductor substrate 10 and the interlayer insulating film 38. The emitter electrode 52 is also formed inside the contact hole and is in contact with the upper surface 21 of the semiconductor substrate 10 exposed by the contact hole.
　コレクタ電極５４は、半導体基板１０の下面２３に形成される。コレクタ電極５４は、半導体基板１０の下面２３全体と接触してよい。エミッタ電極５２およびコレクタ電極５４は、アルミニウム等の金属材料で形成される。 The collector electrode 54 is formed on the lower surface 23 of the semiconductor substrate 10. The collector electrode 54 may contact the entire lower surface 23 of the semiconductor substrate 10. The emitter electrode 52 and the collector electrode 54 are formed of a metal material such as aluminum.
　本例の半導体基板１０には、Ｎ－型のドリフト領域１８、Ｎ＋型のエミッタ領域１２、Ｐ－型のベース領域１４、Ｎ＋型の蓄積領域１６、Ｎ＋型のバッファ領域２０、および、Ｐ＋型のコレクタ領域２２が設けられている。 In the semiconductor substrate 10 of this example, an N− type drift region 18, an N+ type emitter region 12, a P− type base region 14, an N+ type storage region 16, an N+ type buffer region 20, and a P+ type. Collector region 22 is provided.
　エミッタ領域１２は、半導体基板１０の上面２１に接して設けられ、ドリフト領域１８よりもドナー濃度の高い領域である。エミッタ領域１２は、例えばリン等のＮ型不純物を含む。 The emitter region 12 is provided in contact with the upper surface 21 of the semiconductor substrate 10 and has a higher donor concentration than the drift region 18. The emitter region 12 contains an N-type impurity such as phosphorus.
　ベース領域１４は、エミッタ領域１２とドリフト領域１８との間に設けられている。ベース領域１４は、例えばボロン等のＰ型不純物を含む。トレンチ部の延伸方向（図６のＹ軸方向）には、エミッタ領域１２と交互に配置される、図示しないＰ型のコンタクト領域を備える。コンタクト領域はベース領域の上面２１に形成され、エミッタ領域１２よりも深く形成されてよい。コンタクト領域により、ターンオフ時のＩＧＢＴのラッチアップを抑制する。 The base region 14 is provided between the emitter region 12 and the drift region 18. The base region 14 contains a P-type impurity such as boron. In the extending direction of the trench portion (Y-axis direction in FIG. 6 ), P-type contact regions (not shown) alternately arranged with the emitter regions 12 are provided. The contact region is formed on the upper surface 21 of the base region and may be formed deeper than the emitter region 12. The contact region suppresses the latch-up of the IGBT at turn-off.
　蓄積領域１６は、ベース領域１４とドリフト領域１８との間に設けられ、ドリフト領域１８よりもドナー濃度の高い１つ以上のドナー濃度ピークを有する。蓄積領域１６は、リン等のＮ型不純物を含んでよく、水素を含んでいてもよい。 The storage region 16 is provided between the base region 14 and the drift region 18, and has one or more donor concentration peaks having a higher donor concentration than the drift region 18. The storage region 16 may contain N-type impurities such as phosphorus, and may contain hydrogen.
　コレクタ領域２２は、半導体基板１０の下面２３に接して設けられている。コレクタ領域２２のアクセプタ濃度は、ベース領域１４のアクセプタ濃度より高くてよい。コレクタ領域２２は、ベース領域１４と同一のＰ型不純物を含んでよく、異なるＰ型不純物を含んでもよい。 The collector region 22 is provided in contact with the lower surface 23 of the semiconductor substrate 10. The acceptor concentration in the collector region 22 may be higher than the acceptor concentration in the base region 14. The collector region 22 may contain the same P-type impurity as the base region 14 or may contain different P-type impurities.
　バッファ領域２０は、コレクタ領域２２とドリフト領域１８との間に設けられ、ドリフト領域１８よりもドナー濃度の高い１つ以上のドナー濃度ピークを有する。バッファ領域２０は、水素等のＮ型不純物を有する。バッファ領域２０は、ベース領域１４の下面側から広がる空乏層が、コレクタ領域２２に到達することを防ぐフィールドストップ層として機能してよい。 The buffer region 20 is provided between the collector region 22 and the drift region 18, and has one or more donor concentration peaks having a higher donor concentration than the drift region 18. The buffer region 20 has an N-type impurity such as hydrogen. The buffer region 20 may function as a field stop layer that prevents the depletion layer spreading from the lower surface side of the base region 14 from reaching the collector region 22.
　ゲートトレンチ部４０は、半導体基板１０の上面２１から、エミッタ領域１２、ベース領域１４および蓄積領域１６を貫通して、ドリフト領域１８に達している。本例の蓄積領域１６は、ゲートトレンチ部４０の下端よりも上側に配置されている。蓄積領域１６は、ベース領域１４の下面全体を覆うように設けられてよい。ドリフト領域１８とベース領域１４との間に、ドリフト領域１８よりも高濃度の蓄積領域１６を設けることで、キャリア注入促進効果（ＩＥ効果、Ｉｎｊｅｃｔｉｏｎ‐Ｅｎｈａｎｃｅｍｅｎｔ　ｅｆｆｅｃｔ）を高めて、ＩＧＢＴにおけるオン電圧を低減することができる。 The gate trench section 40 reaches the drift region 18 from the upper surface 21 of the semiconductor substrate 10 through the emitter region 12, the base region 14 and the storage region 16. The accumulation region 16 of this example is arranged above the lower end of the gate trench portion 40. The storage region 16 may be provided so as to cover the entire lower surface of the base region 14. By providing the storage region 16 having a higher concentration than the drift region 18 between the drift region 18 and the base region 14, the carrier injection promotion effect (IE effect, injection-enhancement effect) is enhanced, and the on-voltage in the IGBT is increased. It can be reduced.
　ゲートトレンチ部４０は、半導体基板１０の上面側に形成されたゲートトレンチ、ゲート絶縁膜４２およびゲート導電部４４を有する。ゲート絶縁膜４２は、ゲートトレンチの内壁を覆って形成される。ゲート絶縁膜４２は、ゲートトレンチの内壁の半導体を酸化または窒化して形成してよい。ゲート導電部４４は、ゲートトレンチの内部においてゲート絶縁膜４２よりも内側に形成される。つまりゲート絶縁膜４２は、ゲート導電部４４と半導体基板１０とを絶縁する。ゲート導電部４４は、ポリシリコン等の導電材料で形成される。 The gate trench portion 40 has a gate trench formed on the upper surface side of the semiconductor substrate 10, a gate insulating film 42, and a gate conductive portion 44. The gate insulating film 42 is formed so as to cover the inner wall of the gate trench. The gate insulating film 42 may be formed by oxidizing or nitriding the semiconductor on the inner wall of the gate trench. The gate conductive portion 44 is formed inside the gate insulating film 42 inside the gate trench. That is, the gate insulating film 42 insulates the gate conductive portion 44 and the semiconductor substrate 10. The gate conductive portion 44 is formed of a conductive material such as polysilicon.
　ゲート導電部４４は、ゲート絶縁膜４２を挟んでベース領域１４と対向する領域を含む。当該断面におけるゲートトレンチ部４０は、半導体基板１０の上面において層間絶縁膜３８により覆われているが、ゲート導電部４４は、他の断面においてゲート電極と接続されている。ゲート導電部４４に所定のゲート電圧が印加されると、ベース領域１４のうちゲートトレンチ部４０に接する界面の表層に電子の反転層によるチャネルが形成される。 The gate conductive portion 44 includes a region facing the base region 14 with the gate insulating film 42 interposed therebetween. The gate trench portion 40 in the cross section is covered with the interlayer insulating film 38 on the upper surface of the semiconductor substrate 10, but the gate conductive portion 44 is connected to the gate electrode in another cross section. When a predetermined gate voltage is applied to the gate conductive portion 44, a channel formed by an electron inversion layer is formed in the surface layer of the base region 14 at the interface in contact with the gate trench portion 40.
　第１のドナー濃度ピーク１１１は、バッファ領域２０に設けられてよい。第２のドナー濃度ピーク１２１は、バッファ領域２０よりも上方のＮ型の領域に設けられてよい。第２のドナー濃度ピーク１２１は、バッファ領域２０と蓄積領域１６との間に設けられてよい。本例の第２のドナー濃度ピーク１２１は、ドリフト領域１８に設けられている。第２のドナー濃度ピーク１２１は、ゲートトレンチ部４０の下端よりも下側に配置されていてよく、ゲートトレンチ部４０の下端に接して配置されていてよく、ゲートトレンチ部４０の下端より上側に配置されていてもよい。また、第２のドナー濃度ピーク１２１と、蓄積領域１６との間には、基板のベースドーピング濃度Ｄｂの領域であるベースドーピング領域１８０が設けられていてよい。 The first donor concentration peak 111 may be provided in the buffer region 20. The second donor concentration peak 121 may be provided in the N-type region above the buffer region 20. The second donor concentration peak 121 may be provided between the buffer region 20 and the storage region 16. The second donor concentration peak 121 of this example is provided in the drift region 18. The second donor concentration peak 121 may be disposed below the lower end of the gate trench portion 40, may be disposed in contact with the lower end of the gate trench portion 40, and may be disposed above the lower end of the gate trench portion 40. It may be arranged. Further, between the second donor concentration peak 121 and the accumulation region 16, a base doping region 180 which is a region of the substrate base doping concentration Db may be provided.
　図７は、図６のＢ－Ｂ線の位置における、深さ方向のキャリア濃度分布の一例を示す図である。図７においては、水素濃度分布およびヘリウム濃度分布の一部を合わせて示している。図７の縦軸は、対数軸である。 FIG. 7 is a diagram showing an example of the carrier concentration distribution in the depth direction at the position of line BB in FIG. In FIG. 7, a part of the hydrogen concentration distribution and the helium concentration distribution are shown together. The vertical axis of FIG. 7 is a logarithmic axis.
　本例のバッファ領域２０におけるキャリア濃度分布は、深さ方向において異なる位置に設けられた複数のピーク２４を有する。ピーク２４は、ドナー濃度のピークである。ピーク２４は、不純物として水素を有してよい。複数のピーク２４を設けることで、空乏層がコレクタ領域２２に達することを、より抑制できる。第１のドナー濃度ピーク１１１は、バッファ領域２０におけるピーク２４として機能してよい。 The carrier concentration distribution in the buffer region 20 of this example has a plurality of peaks 24 provided at different positions in the depth direction. Peak 24 is the peak of donor concentration. Peak 24 may have hydrogen as an impurity. Providing the plurality of peaks 24 can further prevent the depletion layer from reaching the collector region 22. The first donor concentration peak 111 may function as the peak 24 in the buffer region 20.
　一例として第１のドナー濃度ピーク１１１は、バッファ領域２０の複数のピーク２４のうち、半導体基板１０の下面２３から最も離れたピークとして機能してよい。平坦領域１５０は、バッファ領域２０に含まれる第１のドナー濃度ピーク１１１から、第２のドナー濃度ピーク１２１の間に配置されている。 As an example, the first donor concentration peak 111 may function as a peak farthest from the lower surface 23 of the semiconductor substrate 10 among the plurality of peaks 24 of the buffer region 20. The flat region 150 is arranged between the first donor concentration peak 111 and the second donor concentration peak 121 included in the buffer region 20.
　第１のドナー濃度ピーク１１１は、バッファ領域２０の複数のピーク２４のうち、第１のドナー濃度ピーク１１１の次に下面２３から離れたピーク２４よりも、ドナー濃度が高くてよい。第１のドナー濃度ピーク１１１の濃度を高くすることで、第１のドナー濃度ピーク１１１と第２のドナー濃度ピーク１２１との距離が離れていても、平坦領域１５０を形成しやすくなる。水素濃度分布は、第１の深さＺ１と、下面２３との間に、１つ以上の水素濃度ピーク１９４を有してよい。水素濃度ピーク１９４は、図６等において説明したバッファ領域２０に配置されてよい。水素濃度ピーク１９４は、ピーク２４と同一の深さ位置に配置されてよい。 The first donor concentration peak 111 may have a higher donor concentration than the peak 24 separated from the lower surface 23 next to the first donor concentration peak 111 among the plurality of peaks 24 of the buffer region 20. By increasing the concentration of the first donor concentration peak 111, the flat region 150 can be easily formed even if the distance between the first donor concentration peak 111 and the second donor concentration peak 121 is large. The hydrogen concentration distribution may have one or more hydrogen concentration peaks 194 between the first depth Z1 and the lower surface 23. The hydrogen concentration peak 194 may be arranged in the buffer region 20 described with reference to FIG. The hydrogen concentration peak 194 may be arranged at the same depth position as the peak 24.
　本例の蓄積領域１６は、複数のピーク２５を有している。ピーク２５は、ドナー濃度のピークである。第２のドナー濃度ピーク１２１は、蓄積領域１６よりも、下面２３側に配置されている。第２のドナー濃度ピーク１２１と、蓄積領域１６との間には、基板のベースドーピング濃度Ｄｂの領域（ベースドーピング領域１８０）が設けられていてよい。他の例では、第２のドナー濃度ピーク１２１と、蓄積領域１６との間のドナー濃度は、半導体基板のベースドーピング濃度Ｄｂより高くてもよい。 The storage area 16 in this example has a plurality of peaks 25. Peak 25 is the peak of donor concentration. The second donor concentration peak 121 is arranged on the lower surface 23 side with respect to the accumulation region 16. A region (base doping region 180) having the base doping concentration Db of the substrate may be provided between the second donor concentration peak 121 and the accumulation region 16. In another example, the donor concentration between the second donor concentration peak 121 and the storage region 16 may be higher than the base doping concentration Db of the semiconductor substrate.
　また、半導体装置１００は、半導体基板１０として、半導体インゴット製造時にリン（Ｐ）等のドーパントがインゴット全体にドーピングされないノンドーピング基板を用いてもよい。この場合、半導体基板１０のベースドーピング濃度Ｄｎは、ベースドーピング濃度Ｄｂよりも低い。図７の例では、ドーピング濃度がベースドーピング濃度Ｄｎである領域を、ノンドーピング領域１８１とする。ノンドーピング領域１８１のベースドーピング濃度Ｄｎは、例えば１×１０１０ａｔｏｍｓ／ｃｍ３以上、５×１０１２ａｔｏｍｓ／ｃｍ３以下である。ベースドーピング濃度Ｄｎは、１×１０１１ａｔｏｍｓ／ｃｍ３以上であってよい。ベースドーピング濃度Ｄｎは、５×１０１２ａｔｏｍｓ／ｃｍ３以下であってよい。なお、本明細書における各濃度は、室温における値でよい。室温とは、一例として３００Ｋ（ケルビン）（約２６．９℃）のときの値を用いてよい。 Further, in the semiconductor device 100, as the semiconductor substrate 10, a non-doped substrate in which a dopant such as phosphorus (P) is not doped into the entire ingot during the production of the semiconductor ingot may be used. In this case, the base doping concentration Dn of the semiconductor substrate 10 is lower than the base doping concentration Db. In the example of FIG. 7, the region where the doping concentration is the base doping concentration Dn is the non-doping region 181. The base doping concentration Dn of the non-doping region 181 is, for example, 1×10 10 atoms/cm 3 or more and 5×10 12 atoms/cm 3 or less. The base doping concentration Dn may be 1×10 11 atoms/cm 3 or more. The base doping concentration Dn may be 5×10 12 atoms/cm 3 or less. In addition, each concentration in the present specification may be a value at room temperature. As the room temperature, for example, a value at 300 K (Kelvin) (about 26.9° C.) may be used.
　図８は、半導体装置１００の他の構造例を示す図である。本例の半導体装置１００は、第２のドナー濃度ピーク１２１（および、ヘリウム濃度ピーク１４１）が、蓄積領域１６に配置されている点で、図６および図７において説明した半導体装置１００と相違する。他の構造は、図６および図７において説明した半導体装置１００と同一であってよい。 FIG. 8 is a diagram showing another structural example of the semiconductor device 100. The semiconductor device 100 of this example is different from the semiconductor device 100 described in FIGS. 6 and 7 in that the second donor concentration peak 121 (and the helium concentration peak 141) is arranged in the accumulation region 16. .. The other structure may be the same as that of the semiconductor device 100 described in FIGS. 6 and 7.
　図９は、図８のＣ－Ｃ線の位置における、深さ方向のキャリア濃度分布の一例を示す図である。図９においては、水素濃度分布およびヘリウム濃度分布の一部を合わせて示している。図９の縦軸は、対数軸である。 FIG. 9 is a diagram showing an example of the carrier concentration distribution in the depth direction at the position of the line CC of FIG. In FIG. 9, a part of the hydrogen concentration distribution and the helium concentration distribution are shown together. The vertical axis of FIG. 9 is a logarithmic axis.
　本例の蓄積領域１６におけるキャリア濃度分布は、深さ方向において異なる位置に設けられた複数のピークを有する。当該ピークは、ドナー濃度のピークである。蓄積領域１６におけるピークは、不純物として水素またはリンを有してよい。蓄積領域１６に複数のピークを設けることで、ゲートトレンチ部とダミートレンチ部とが隣り合って配置された構造において、ゲートトレンチ部への変位電流を抑制できる（例えば、ＷＯ２０１８／０３０４４０参照）。ダミートレンチ部は、ゲートトレンチ部と同様の構造を有しており、エミッタ電位が印加されるトレンチ部である。 The carrier concentration distribution in the storage region 16 of this example has a plurality of peaks provided at different positions in the depth direction. The peak is a peak of donor concentration. The peak in the accumulation region 16 may have hydrogen or phosphorus as an impurity. By providing a plurality of peaks in the storage region 16, a displacement current to the gate trench portion can be suppressed in a structure in which the gate trench portion and the dummy trench portion are arranged adjacent to each other (see, for example, WO2018/030440). The dummy trench portion has the same structure as the gate trench portion, and is a trench portion to which the emitter potential is applied.
　本例の第２のドナー濃度ピーク１２１は、蓄積領域１６におけるいずれかのドナー濃度ピークとして機能する。一例として第２のドナー濃度ピーク１２１は、蓄積領域１６の複数のピークのうち、半導体基板１０の上面２１から最も離れたピークとして機能してよい。本例の平坦領域１５０は、バッファ領域２０に含まれる第１のドナー濃度ピーク１１１から、蓄積領域１６に含まれる第２のドナー濃度ピーク１２１の間に配置されている。 The second donor concentration peak 121 of this example functions as one of the donor concentration peaks in the accumulation region 16. As an example, the second donor concentration peak 121 may function as a peak farthest from the upper surface 21 of the semiconductor substrate 10 among the plurality of peaks of the accumulation region 16. The flat region 150 of this example is arranged between the first donor concentration peak 111 included in the buffer region 20 and the second donor concentration peak 121 included in the accumulation region 16.
　第２のドナー濃度ピーク１２１のドナー濃度は、バッファ領域２０の他のピーク２５のドナー濃度に対して低くてよく、同一であってよく、高くてもよい。バッファ領域２０が３以上のピークを有する場合、第２のドナー濃度ピーク１２１以外のピーク２５のドナー濃度は同一であってよい。第２のドナー濃度ピーク１２１のドナー濃度は、平坦領域１５０が有するべきドナー濃度に応じて定められてよい。 The donor concentration of the second donor concentration peak 121 may be lower than, the same as, or higher than the donor concentration of the other peak 25 of the buffer region 20. When the buffer region 20 has three or more peaks, the peak 25 other than the second donor concentration peak 121 may have the same donor concentration. The donor concentration of the second donor concentration peak 121 may be set according to the donor concentration that the flat region 150 should have.
　本例のドリフト領域１８のキャリア濃度は、深さ方向の全体にわたって、基板のベースドーピング濃度Ｄｂよりも高くてよい。このような構造により、ドリフト領域１８のキャリア濃度全体を精度よく調整できる。 The carrier concentration of the drift region 18 of this example may be higher than the base doping concentration Db of the substrate over the entire depth direction. With such a structure, the entire carrier concentration of the drift region 18 can be adjusted accurately.
　第２のドナー濃度ピーク１２１以外のピーク２５は、水素以外のドナーによるピークであってよい。例えばピーク２５は、リンがドナーとして機能しているピークである。ドナーとしてリンを用いることでＶＯＨ欠陥が生じにくくなり、ピーク２５およびその近傍のドナー濃度をリンの濃度で制御しやすくなる。さらに、第２のドナー濃度ピーク１２１の深さ方向の幅を、ピーク２５の深さ方向の幅よりも広くしてよい。これにより、ゲートトレンチ部への変位電流をさらに抑制することができる。また、蓄積領域１６の第２のドナー濃度ピーク１２１とピーク２５の間には、図９に示すようにドナー濃度分布の谷があってよい。あるいは、図９の当該２つのピーク間で点線で示すように、蓄積領域１６のドナー濃度分布が、谷ではなくキンクになっていてもよい。 The peak 25 other than the second donor concentration peak 121 may be a peak due to a donor other than hydrogen. For example, peak 25 is a peak in which phosphorus functions as a donor. By using phosphorus as the donor, VOH defects are less likely to occur, and the donor concentration in the peak 25 and its vicinity can be easily controlled by the phosphorus concentration. Further, the width of the second donor concentration peak 121 in the depth direction may be wider than the width of the peak 25 in the depth direction. Thereby, the displacement current to the gate trench portion can be further suppressed. Further, a valley of the donor concentration distribution may be present between the second donor concentration peak 121 and the peak 25 of the accumulation region 16 as shown in FIG. Alternatively, as shown by a dotted line between the two peaks in FIG. 9, the donor concentration distribution in the accumulation region 16 may be a kink instead of a valley.
　図１０は、図１のＡ－Ａ線に示した位置における、深さ方向の水素濃度分布、ヘリウム濃度分布およびキャリア濃度分布を示している。キャリア濃度はＳＲ法で測定した。ヘリウム濃度ピーク１４１の飛程（Ｚ２）の近傍には、通過領域１０６よりも多くの欠陥が発生しやすい。水素と結合せずに残った欠陥により、第２の深さＺ２の近傍におけるキャリア濃度分布に谷１５１が生じる場合がある。 FIG. 10 shows the hydrogen concentration distribution, the helium concentration distribution, and the carrier concentration distribution in the depth direction at the position shown by the line AA in FIG. The carrier concentration was measured by SR method. More defects are more likely to occur in the vicinity of the range (Z2) of the helium concentration peak 141 than in the passage region 106. The defect remaining without being bonded to hydrogen may cause a valley 151 in the carrier concentration distribution in the vicinity of the second depth Z2.
　谷１５１が生じていると、第２のドナー濃度ピーク１２１の上りスロープ１２２の傾きが、計算上急峻になる場合がある。このため、上りスロープ１２２の傾きは、谷１５１の影響を除外して計算することが好ましい。例えば、第２のドナー濃度ピーク１２１およびヘリウム濃度ピーク１４１の各上りスロープの傾きを、第２の深さＺ２における各濃度と、深さＺｃにおける各濃度を用いて計算してよい。深さＺｃは、谷１５１よりも下面２３側の位置であってよい。本例において深さＺｃは、平坦領域１５０の深さ方向における中央の深さである。これにより、谷１５１の影響を除外して、第２のドナー濃度ピーク１２１の上りスロープ１２２の傾きを規格化できる。規格化は上述のように、濃度差の傾きを用いてもよく、濃度の比の傾きを用いてもよい。 When the valley 151 is generated, the slope of the upward slope 122 of the second donor concentration peak 121 may be steep in calculation. Therefore, it is preferable to calculate the slope of the uphill slope 122 by excluding the influence of the valley 151. For example, the slopes of the upward slopes of the second donor concentration peak 121 and the helium concentration peak 141 may be calculated using the concentrations at the second depth Z2 and the concentrations at the depth Zc. The depth Zc may be a position closer to the lower surface 23 than the valley 151. In this example, the depth Zc is the central depth of the flat region 150 in the depth direction. As a result, the influence of the valley 151 can be excluded and the slope of the upward slope 122 of the second donor concentration peak 121 can be standardized. As described above, the standardization may use the gradient of the density difference or the gradient of the density ratio.
　図１１は、半導体基板１０の上面２１における各要素の配置例を示す図である。図１１においては、半導体基板１０の外周の端部を外周端１４０とする。 FIG. 11 is a diagram showing an arrangement example of each element on the upper surface 21 of the semiconductor substrate 10. In FIG. 11, the outer peripheral edge of the semiconductor substrate 10 is defined as the outer peripheral edge 140.
　半導体装置１００は、活性部１２０およびエッジ終端構造部９０を備える。活性部１２０は、半導体装置１００をオン状態に制御した場合に半導体基板１０の上面２１と下面２３との間で主電流が流れる領域である。即ち、半導体基板１０の上面２１から下面２３、または下面２３から上面２１に、半導体基板１０の内部を深さ方向に電流が流れる領域である。 The semiconductor device 100 includes an active section 120 and an edge termination structure section 90. The active portion 120 is a region in which a main current flows between the upper surface 21 and the lower surface 23 of the semiconductor substrate 10 when the semiconductor device 100 is controlled to be in the ON state. That is, it is a region in the semiconductor substrate 10 where current flows in the depth direction from the upper surface 21 to the lower surface 23 or from the lower surface 23 to the upper surface 21.
　本例の活性部１２０には、トランジスタ部７０およびダイオード部８０が設けられている。トランジスタ部７０およびダイオード部８０は、Ｘ軸方向に並んで配置されてよい。図１１の例では、トランジスタ部７０およびダイオード部８０が、Ｘ軸方向に交互に接して配置されている。活性部１２０において、Ｘ軸方向における両端には、トランジスタ部７０が設けられてよい。エミッタ電極５２は、トランジスタ部７０およびダイオード部８０を覆っていてよい。活性部１２０は、エミッタ電極５２で覆われた領域を指してもよい。 The active section 120 of this example is provided with a transistor section 70 and a diode section 80. The transistor unit 70 and the diode unit 80 may be arranged side by side in the X-axis direction. In the example of FIG. 11, the transistor section 70 and the diode section 80 are arranged alternately in contact with each other in the X-axis direction. The transistor section 70 may be provided at both ends of the active section 120 in the X-axis direction. The emitter electrode 52 may cover the transistor section 70 and the diode section 80. The active part 120 may refer to a region covered with the emitter electrode 52.
　本例のトランジスタ部７０は、図６から図１０において説明したＩＧＢＴ（ゲート絶縁型バイポーラトランジスタ）を有する。本例のダイオード部８０は、ＦＷＤ（還流ダイオード）を有する。それぞれのダイオード部８０には、半導体基板１０の下面２３に接する領域にＮ＋型のカソード領域８２が設けられている。図１１において、実線で示すダイオード部８０は、半導体基板１０の下面２３にカソード領域８２が設けられた領域である。本例の半導体装置１００において、半導体基板１０の下面２３に接する領域のうち、カソード領域８２以外の領域には、コレクタ領域２２が設けられる。 The transistor unit 70 of this example has the IGBT (gate insulation type bipolar transistor) described in FIGS. 6 to 10. The diode unit 80 of this example has an FWD (free wheeling diode). In each diode portion 80, an N+ type cathode region 82 is provided in a region in contact with the lower surface 23 of the semiconductor substrate 10. In FIG. 11, the diode portion 80 shown by the solid line is a region where the cathode region 82 is provided on the lower surface 23 of the semiconductor substrate 10. In the semiconductor device 100 of this example, the collector region 22 is provided in a region other than the cathode region 82 in the region in contact with the lower surface 23 of the semiconductor substrate 10.
　ダイオード部８０は、カソード領域８２をＺ軸方向に投影した領域である。トランジスタ部７０は、半導体基板１０の下面２３にコレクタ領域２２が設けられ、且つ、半導体基板１０の上面２１にエミッタ領域１２を含む単位構造が周期的に設けられた領域である。Ｙ軸方向におけるダイオード部８０とトランジスタ部７０との境界は、カソード領域８２とコレクタ領域２２との境界である。カソード領域８２を投影した領域を、Ｙ軸方向に活性部１２０の端部またはゲートランナー４８まで伸ばした部分（図１１において、ダイオード部８０を延長した破線で示される部分）も、ダイオード部８０に含めてよい。当該延長部分には、エミッタ領域１２が設けられていない。 The diode part 80 is a region obtained by projecting the cathode region 82 in the Z-axis direction. The transistor part 70 is a region in which the collector region 22 is provided on the lower surface 23 of the semiconductor substrate 10 and the unit structure including the emitter region 12 is periodically provided on the upper surface 21 of the semiconductor substrate 10. The boundary between the diode portion 80 and the transistor portion 70 in the Y-axis direction is the boundary between the cathode region 82 and the collector region 22. A portion of the projected region of the cathode region 82 extending to the end of the active portion 120 or the gate runner 48 in the Y-axis direction (the portion shown by the broken line of the extended diode portion 80 in FIG. 11) is also included in the diode portion 80. May be included. The extension region is not provided with the emitter region 12.
　本例の半導体装置１００は、ゲート金属層５０およびゲートランナー４８を更に備えている。また半導体装置１００は、ゲートパッド１１６およびエミッタパッド１１８等の各パッドを有してよい。ゲートパッド１１６は、ゲート金属層５０およびゲートランナー４８と電気的に接続されている。エミッタパッド１１８は、エミッタ電極５２と電気的に接続されている。 The semiconductor device 100 of this example further includes a gate metal layer 50 and a gate runner 48. Further, the semiconductor device 100 may have each pad such as the gate pad 116 and the emitter pad 118. The gate pad 116 is electrically connected to the gate metal layer 50 and the gate runner 48. The emitter pad 118 is electrically connected to the emitter electrode 52.
　ゲート金属層５０は、上面視で活性部１２０を囲うように設けられてよい。ゲートパッド１１６およびエミッタパッド１１８は、ゲート金属層５０に囲まれた領域内に配置されてよい。ゲート金属層５０は、アルミニウム、または、アルミニウムシリコン合金等の金属材料で形成されてよい。ゲート金属層５０は、層間絶縁膜３８により半導体基板１０と絶縁されている。図１１においては、層間絶縁膜３８を省略している。また、ゲート金属層５０は、エミッタ電極５２とは分離して設けられている。ゲート金属層５０は、ゲートパッド１１６に印加されたゲート電圧をトランジスタ部７０に伝達する。トランジスタ部７０のゲート導電部４４は、ゲート金属層５０に直接接続され、または、他の導電部材を介して間接的に接続されている。 The gate metal layer 50 may be provided so as to surround the active portion 120 in a top view. The gate pad 116 and the emitter pad 118 may be located in the region surrounded by the gate metal layer 50. The gate metal layer 50 may be formed of a metal material such as aluminum or an aluminum silicon alloy. The gate metal layer 50 is insulated from the semiconductor substrate 10 by the interlayer insulating film 38. In FIG. 11, the interlayer insulating film 38 is omitted. The gate metal layer 50 is provided separately from the emitter electrode 52. The gate metal layer 50 transfers the gate voltage applied to the gate pad 116 to the transistor unit 70. The gate conductive portion 44 of the transistor portion 70 is directly connected to the gate metal layer 50 or indirectly connected via another conductive member.
　ゲートランナー４８は、ゲート金属層５０と、ゲート導電部４４とを接続する。ゲートランナー４８は、不純物がドープされたポリシリコン等の半導体材料で形成されてよい。ゲートランナー４８の一部は、活性部１２０の上方に設けられてよい。図１１に示すゲートランナー４８は、活性部１２０をＸ軸方向に横切って設けられている。これにより、ゲート金属層５０から離れた活性部１２０の内側においても、ゲート電圧の低下および遅延を抑制できる。ゲートランナー４８の一部は、ゲート金属層５０に沿って、活性部１２０を囲んで配置されていてもよい。ゲートランナー４８は、活性部１２０の端部において、ゲート導電部４４と接続されてよい。 The gate runner 48 connects the gate metal layer 50 and the gate conductive portion 44. The gate runner 48 may be formed of a semiconductor material such as polysilicon doped with impurities. A part of the gate runner 48 may be provided above the active portion 120. The gate runner 48 shown in FIG. 11 is provided across the active portion 120 in the X-axis direction. As a result, it is possible to suppress the decrease and delay of the gate voltage even inside the active portion 120, which is separated from the gate metal layer 50. A part of the gate runner 48 may be disposed along the gate metal layer 50 so as to surround the active portion 120. The gate runner 48 may be connected to the gate conductive portion 44 at the end of the active portion 120.
　エッジ終端構造部９０は、半導体基板１０の上面２１において、活性部１２０と半導体基板１０の外周端１４０との間に設けられる。本例では、エッジ終端構造部９０と活性部１２０との間に、ゲート金属層５０が配置されている。エッジ終端構造部９０は、半導体基板１０の上面２１において活性部１２０を囲むように環状に配置されてよい。本例のエッジ終端構造部９０は、半導体基板１０の外周端１４０に沿って配置されている。エッジ終端構造部９０は、半導体基板１０の上面２１側の電界集中を緩和する。エッジ終端構造部９０は、例えばガードリング、フィールドプレート、リサーフおよびこれらを組み合わせた構造を有する。 The edge termination structure portion 90 is provided on the upper surface 21 of the semiconductor substrate 10 between the active portion 120 and the outer peripheral end 140 of the semiconductor substrate 10. In this example, the gate metal layer 50 is arranged between the edge termination structure portion 90 and the active portion 120. The edge termination structure portion 90 may be annularly arranged on the upper surface 21 of the semiconductor substrate 10 so as to surround the active portion 120. The edge termination structure 90 of this example is arranged along the outer peripheral edge 140 of the semiconductor substrate 10. The edge termination structure portion 90 relaxes electric field concentration on the upper surface 21 side of the semiconductor substrate 10. The edge termination structure 90 has, for example, a guard ring, a field plate, a RESURF, and a structure combining these.
　図１２は、図１１におけるｃ－ｃ'断面の一例を示す図である。図１２においては、図１から図１０において説明した通過領域１０６の、当該断面における配置例を示している。図１２においては、通過領域１０６に斜線のハッチングを付している。なお図１２では、ドリフト領域１８における通過領域１０６のみを示しており、バッファ領域２０、コレクタ領域２２およびカソード領域８２における通過領域１０６は省略している。 FIG. 12 is a diagram showing an example of a cc′ cross section in FIG. 11. FIG. 12 shows an arrangement example of the passage area 106 described in FIGS. 1 to 10 in the cross section. In FIG. 12, the passage area 106 is hatched. Note that FIG. 12 shows only the passage region 106 in the drift region 18, and omits the passage regions 106 in the buffer region 20, the collector region 22, and the cathode region 82.
　図１２に示す断面は、エッジ終端構造部９０、トランジスタ部７０およびダイオード部８０を含むＸＺ面である。なお、エッジ終端構造部９０およびトランジスタ部７０の間には、ゲート金属層５０およびゲートランナー４８が配置されているが、図１２では省略している。トランジスタ部７０の構造は、図６から図１０において説明したＩＧＢＴと同様である。 The cross section shown in FIG. 12 is an XZ plane including the edge termination structure portion 90, the transistor portion 70, and the diode portion 80. Although the gate metal layer 50 and the gate runner 48 are disposed between the edge termination structure portion 90 and the transistor portion 70, they are omitted in FIG. The structure of the transistor unit 70 is similar to that of the IGBT described in FIGS. 6 to 10.
　ダイオード部８０は、半導体基板１０の内部において、ベース領域１４、ドリフト領域１８、カソード領域８２およびダミートレンチ部３０を備える。ベース領域１４およびドリフト領域１８は、トランジスタ部７０におけるベース領域１４およびドリフト領域１８と同一である。 The diode portion 80 includes the base region 14, the drift region 18, the cathode region 82, and the dummy trench portion 30 inside the semiconductor substrate 10. The base region 14 and the drift region 18 are the same as the base region 14 and the drift region 18 in the transistor section 70.
　ダイオード部８０において半導体基板１０の上面２１に接する領域には、ベース領域１４が設けられていてよく、コンタクト領域１５が設けられていてもよい。コンタクト領域１５は、ベース領域１４よりもドーピング濃度の高いＰ＋型の領域である。本例のダイオード部８０には、エミッタ領域１２は設けられていない。また、ダイオード部８０には、蓄積領域１６が設けられていてよく、設けられていなくともよい。 The base region 14 may be provided in a region of the diode portion 80 that is in contact with the upper surface 21 of the semiconductor substrate 10, and the contact region 15 may be provided. The contact region 15 is a P+ type region having a higher doping concentration than the base region 14. The diode region 80 of this example is not provided with the emitter region 12. Further, the diode portion 80 may or may not be provided with the storage region 16.
　ダミートレンチ部３０は、ゲートトレンチ部４０と同一の構造を有する。ただしダミートレンチ部３０は、エミッタ電極５２と電気的に接続されている。ダミートレンチ部３０は、半導体基板１０の上面２１から、ベース領域１４を貫通して、ドリフト領域１８まで設けられている。ダミートレンチ部３０は、トランジスタ部７０にも設けられてよい。トランジスタ部７０には、ダミートレンチ部３０とゲートトレンチ部４０とが、予め定められた周期で配置されてよい。 The dummy trench section 30 has the same structure as the gate trench section 40. However, the dummy trench portion 30 is electrically connected to the emitter electrode 52. The dummy trench portion 30 is provided from the upper surface 21 of the semiconductor substrate 10 to the drift region 18 through the base region 14. The dummy trench section 30 may also be provided in the transistor section 70. The dummy trench portion 30 and the gate trench portion 40 may be arranged in the transistor portion 70 at a predetermined cycle.
　トランジスタ部７０とダイオード部８０の間には、中間境界領域１９０があってよい。中間境界領域１９０は、トランジスタ部７０の動作もダイオード部８０の動作も直接的に行わない領域である。一例として、中間境界領域１９０の上面２１に接する領域は、ダイオード部８０の上面２１側と同じ構造を有してよい。また、上面視で、中間境界領域１９０の下面２３に接する領域には、トランジスタ部７０のコレクタ領域が延伸して設けられてよい。図１２においては、中間境界領域１９０の範囲例だけを矢印で示している。図１２においては、中間境界領域１９０として例示した範囲も、トランジスタ部７０と同一の構造になっている。 There may be an intermediate boundary region 190 between the transistor section 70 and the diode section 80. The intermediate boundary region 190 is a region in which neither the operation of the transistor unit 70 nor the operation of the diode unit 80 is directly performed. As an example, the region in contact with the upper surface 21 of the intermediate boundary region 190 may have the same structure as the upper surface 21 side of the diode unit 80. Further, the collector region of the transistor unit 70 may be provided so as to extend in a region in contact with the lower surface 23 of the intermediate boundary region 190 in a top view. In FIG. 12, only the range example of the intermediate boundary region 190 is indicated by an arrow. In FIG. 12, the range illustrated as the intermediate boundary region 190 has the same structure as the transistor unit 70.
　ダイオード部８０のドリフト領域１８で、深さ方向の中心よりも上面２１側には、ライフタイム制御領域１９２が設けられてよい。ライフタイム制御領域１９２は、キャリア（電子または正孔）の再結合中心が、周辺よりも高い濃度で設けられた領域である。再結合中心は、空孔や複空孔などの空孔系の欠陥であってよく、転位であってよく、格子間原子であってよく、遷移金属等であってよい。ライフタイム制御領域１９２は、ダイオード部８０から中間境界領域１９０まで延伸してよい。 In the drift region 18 of the diode portion 80, the lifetime control region 192 may be provided on the upper surface 21 side with respect to the center in the depth direction. The lifetime control region 192 is a region in which the recombination center of carriers (electrons or holes) is provided at a higher concentration than the periphery. The recombination center may be a vacancy-based defect such as a vacancy or a double vacancy, a dislocation, an interstitial atom, or a transition metal. The lifetime control region 192 may extend from the diode portion 80 to the intermediate boundary region 190.
　エッジ終端構造部９０には、複数のガードリング９２、複数のフィールドプレート９４およびチャネルストッパ１７４が設けられている。エッジ終端構造部９０において、下面２３に接する領域には、コレクタ領域２２が設けられていてよい。各ガードリング９２は、上面２１において活性部１２０を囲むように設けられてよい。複数のガードリング９２は、活性部１２０において発生した空乏層を半導体基板１０の外側へ広げる機能を有してよい。これにより、半導体基板１０内部における電界集中を防ぐことができ、半導体装置１００の耐圧を向上できる。 The edge termination structure 90 is provided with a plurality of guard rings 92, a plurality of field plates 94 and a channel stopper 174. In the edge termination structure portion 90, the collector region 22 may be provided in a region in contact with the lower surface 23. Each guard ring 92 may be provided on the upper surface 21 so as to surround the active portion 120. The plurality of guard rings 92 may have a function of spreading the depletion layer generated in the active portion 120 to the outside of the semiconductor substrate 10. Thereby, the electric field concentration inside the semiconductor substrate 10 can be prevented, and the breakdown voltage of the semiconductor device 100 can be improved.
　本例のガードリング９２は、上面２１近傍にイオン注入により形成されたＰ＋型の半導体領域である。ガードリング９２の底部の深さは、ゲートトレンチ部４０およびダミートレンチ部３０の底部の深さより深くてよい。 The guard ring 92 of this example is a P+ type semiconductor region formed by ion implantation near the upper surface 21. The bottom of the guard ring 92 may be deeper than the bottoms of the gate trench portion 40 and the dummy trench portion 30.
　ガードリング９２の上面は、層間絶縁膜３８により覆われている。フィールドプレート９４は、金属またはポリシリコン等の導電材料で形成される。フィールドプレート９４は、ゲート金属層５０またはエミッタ電極５２と同じ材料で形成されてよい。フィールドプレート９４は、層間絶縁膜３８上に設けられている。フィールドプレート９４は、層間絶縁膜３８に設けられた貫通孔を通って、ガードリング９２に接続されている。 The upper surface of the guard ring 92 is covered with the interlayer insulating film 38. The field plate 94 is formed of a conductive material such as metal or polysilicon. The field plate 94 may be formed of the same material as the gate metal layer 50 or the emitter electrode 52. The field plate 94 is provided on the interlayer insulating film 38. The field plate 94 is connected to the guard ring 92 through a through hole provided in the interlayer insulating film 38.
　半導体基板１０の上面２１側には、保護膜１８２が設けられる。保護膜１８２は、エッジ終端構造部９０、ゲート金属層５０、境界部７２および活性部のうち境界部７２に接する部分の一部などを覆ってよい。保護膜１８２は、絶縁性膜、有機薄膜であってよい。本例の保護膜１８２はポリイミドである。エミッタ電極５２のうち保護膜１８２が形成されておらずに露出する部分の全面に、めっき層１８４が設けられてよい。めっき層１８４の表面は保護膜１８２の表面よりも上面２１側に位置してよい。めっき層１８４は、半導体装置１００が実装されるパワーモジュールの電極端子と接続している。 A protective film 182 is provided on the upper surface 21 side of the semiconductor substrate 10. The protective film 182 may cover the edge termination structure portion 90, the gate metal layer 50, the boundary portion 72, and a part of a portion in contact with the boundary portion 72 among the active portions. The protective film 182 may be an insulating film or an organic thin film. The protective film 182 of this example is polyimide. The plating layer 184 may be provided on the entire surface of the exposed portion of the emitter electrode 52 where the protective film 182 is not formed. The surface of the plating layer 184 may be located closer to the upper surface 21 side than the surface of the protective film 182. The plating layer 184 is connected to the electrode terminals of the power module on which the semiconductor device 100 is mounted.
　チャネルストッパ１７４は、外周端１４０における上面２１および側面に露出して設けられる。チャネルストッパ１７４は、ドリフト領域１８よりもドーピング濃度の高いＮ型の領域である。チャネルストッパ１７４は、活性部１２０において発生した空乏層を半導体基板１０の外周端１４０において終端させる機能を有する。 The channel stopper 174 is provided so as to be exposed on the upper surface 21 and the side surface at the outer peripheral end 140. The channel stopper 174 is an N-type region having a higher doping concentration than the drift region 18. The channel stopper 174 has a function of terminating the depletion layer generated in the active portion 120 at the outer peripheral edge 140 of the semiconductor substrate 10.
　トランジスタ部７０と、エッジ終端構造部９０との間には、境界部７２が設けられていてもよい。境界部７２は、半導体基板１０の上面２１側において、コンタクト領域１５、ベース領域１４およびダミートレンチ部３０を有してよい。境界部７２は、ベース領域１４よりもドーピング濃度の高いＰ＋型のウェル領域１１を有してよい。ウェル領域１１は、半導体基板１０の上面２１に接して設けられる。ウェル領域１１の上方には、ゲート金属層５０およびゲートランナー４８が設けられてよい。ウェル領域１１の底部の深さは、ガードリング９２の底部と同じ深さであってよい。境界部７２における一部のトレンチ部は、ウェル領域１１内に形成されてよい。境界部７２において、下面２３に接する領域には、コレクタ領域２２が設けられていてよい。 A boundary portion 72 may be provided between the transistor portion 70 and the edge termination structure portion 90. The boundary portion 72 may have the contact region 15, the base region 14, and the dummy trench portion 30 on the upper surface 21 side of the semiconductor substrate 10. The boundary portion 72 may include the P+ type well region 11 having a higher doping concentration than the base region 14. The well region 11 is provided in contact with the upper surface 21 of the semiconductor substrate 10. A gate metal layer 50 and a gate runner 48 may be provided above the well region 11. The bottom of the well region 11 may have the same depth as the bottom of the guard ring 92. A part of the trench portion in the boundary portion 72 may be formed in the well region 11. The collector region 22 may be provided in a region of the boundary portion 72 in contact with the lower surface 23.
　本例では、ヘリウム濃度ピーク１４１は、ゲートトレンチ部４０のＺ軸方向における底部と、半導体基板１０の上面２１との間に配置されている。図１２の例では、ヘリウム濃度ピーク１４１は、蓄積領域１６よりも深い位置に配置されているが、ヘリウム濃度ピーク１４１は、蓄積領域１６と同じ深さに配置されていてよく、ベース領域１４と同じ深さに配置されていてよく、エミッタ領域１２と同じ深さに配置されていてもよい。なお、蓄積領域１６は、図１２の点線で示すように、ダイオード部８０にも形成されてよい。 In this example, the helium concentration peak 141 is arranged between the bottom portion of the gate trench portion 40 in the Z-axis direction and the upper surface 21 of the semiconductor substrate 10. In the example of FIG. 12, the helium concentration peak 141 is arranged at a position deeper than the accumulation region 16, but the helium concentration peak 141 may be arranged at the same depth as the accumulation region 16, and the helium concentration peak 141 and the base region 14 may be arranged. It may be arranged at the same depth, or may be arranged at the same depth as the emitter region 12. The storage region 16 may also be formed in the diode portion 80 as shown by the dotted line in FIG.
　通過領域１０６は、半導体基板１０の下面２３から、ヘリウム濃度ピーク１４１までの範囲に形成される。各図においては、ヘリウム濃度ピーク１４１と通過領域１０６とは重なっていないが、通過領域１０６は、ヘリウム濃度ピーク１４１の深さまで形成されている。 The passage region 106 is formed in the range from the lower surface 23 of the semiconductor substrate 10 to the helium concentration peak 141. In each figure, the helium concentration peak 141 and the passage region 106 do not overlap each other, but the passage region 106 is formed up to the depth of the helium concentration peak 141.
　また本例の通過領域１０６は、トランジスタ部７０、ダイオード部８０、境界部７２およびエッジ終端構造部９０のそれぞれに設けられている。トランジスタ部７０、ダイオード部８０、境界部７２およびエッジ終端構造部９０のそれぞれにおいて、通過領域１０６の深さは同一であってよい。通過領域１０６は、半導体基板１０の上面視における全体に設けられてもよい。本例によれば、半導体基板１０の深さ方向のほぼ全体にわたって、ドナー濃度を調整できる。また、半導体基板１０の上面視におけるほぼ全体にわたって、ドナー濃度を調整できる。 Further, the passage region 106 of this example is provided in each of the transistor section 70, the diode section 80, the boundary section 72, and the edge termination structure section 90. In each of the transistor part 70, the diode part 80, the boundary part 72, and the edge termination structure part 90, the depth of the passage region 106 may be the same. The passage region 106 may be provided in the entire top view of the semiconductor substrate 10. According to this example, the donor concentration can be adjusted over almost the entire depth of the semiconductor substrate 10. Further, the donor concentration can be adjusted over almost the entire top surface of the semiconductor substrate 10.
　本例では、通過領域１０６が形成されない領域が、特にエッジ終端構造部９０の上面２１に接する部分に設けられる。この通過領域１０６が形成されない領域は、ドナー濃度がベースドーピング濃度Ｄｂと同じになる部分である。通過領域１０６が形成されない領域は、ヘリウム濃度ピーク１４１の深さよりも上面２１側となる。つまり、通過領域１０６が形成されない領域は、ドーピング濃度がほぼベースドーピング濃度Ｄｂとなる領域であってよい。ドーピング濃度がベースドーピング濃度Ｄｂである領域を、ベースドーピング領域１８０とする。本例では、ベースドーピング領域１８０は、上面２１に接してウェル領域１１より浅い部分に設けられる。 In this example, a region where the passage region 106 is not formed is provided particularly in a portion in contact with the upper surface 21 of the edge termination structure portion 90. The region where the passage region 106 is not formed is a portion where the donor concentration becomes the same as the base doping concentration Db. A region where the passage region 106 is not formed is on the upper surface 21 side with respect to the depth of the helium concentration peak 141. That is, the region where the passage region 106 is not formed may be a region where the doping concentration is almost the base doping concentration Db. The region where the doping concentration is the base doping concentration Db is referred to as the base doping region 180. In this example, the base doping region 180 is provided in contact with the upper surface 21 and in a portion shallower than the well region 11.
　図１３は、通過領域１０６の他の配置例を示す図である。本例の通過領域１０６は、図１２における通過領域１０６に対して、深さ方向における幅が異なる。上面視における配置は、図１２における通過領域１０６と同一である。 FIG. 13 is a diagram showing another arrangement example of the passage area 106. The passage area 106 of this example is different from the passage area 106 in FIG. 12 in width in the depth direction. The arrangement in a top view is the same as the passage area 106 in FIG.
　本例のヘリウム濃度ピーク１４１は、ゲートトレンチ部４０の底部と、半導体基板１０の下面２３との間に配置されている。半導体基板１０の深さ方向における厚みをＴ１、ヘリウム濃度ピーク１４１と半導体基板１０の下面２３との距離をＴ２とする。距離Ｔ２は、通過領域１０６の深さ方向における厚みに対応する。距離Ｔ２は、厚みＴ１の４０％以上、６０％以下であってよい。つまり、通過領域１０６は、半導体基板１０の下面２３から、半導体基板１０の深さ方向におけるほぼ中央まで設けられていてよい。ただし、距離Ｔ２は適宜変更できる。 The helium concentration peak 141 of this example is arranged between the bottom of the gate trench 40 and the lower surface 23 of the semiconductor substrate 10. The thickness of the semiconductor substrate 10 in the depth direction is T1, and the distance between the helium concentration peak 141 and the lower surface 23 of the semiconductor substrate 10 is T2. The distance T2 corresponds to the thickness of the passage area 106 in the depth direction. The distance T2 may be 40% or more and 60% or less of the thickness T1. That is, the passage region 106 may be provided from the lower surface 23 of the semiconductor substrate 10 to almost the center in the depth direction of the semiconductor substrate 10. However, the distance T2 can be changed as appropriate.
　上述のようにベースドーピング領域１８０は、ヘリウム濃度ピーク１４１よりも上面２１側に設けられる。本例のベースドーピング領域１８０は、トレンチ部の底面からヘリウム濃度ピーク１４１までの領域であり、およそＴ１－Ｔ２の深さを有する。上面視では、本例のベースドーピング領域１８０は半導体基板１０の全面に設けられる。 As described above, the base doping region 180 is provided on the upper surface 21 side of the helium concentration peak 141. The base doping region 180 of this example is a region from the bottom surface of the trench portion to the helium concentration peak 141, and has a depth of about T1-T2. In a top view, the base doping region 180 of this example is provided on the entire surface of the semiconductor substrate 10.
　図１４は、通過領域１０６の他の配置例を示す図である。本例の通過領域１０６は、図１２における通過領域１０６に対して、上面視における配置が異なる。深さ方向における配置は、図１２における通過領域１０６と同一であってよい。 FIG. 14 is a diagram showing another arrangement example of the passage area 106. The passage area 106 of the present example is different from the passage area 106 in FIG. 12 in the arrangement in top view. The arrangement in the depth direction may be the same as the passage area 106 in FIG.
　本例では、上面視におけるエッジ終端構造部９０の少なくとも一部の領域には、通過領域１０６およびヘリウム濃度ピーク１４１が設けられていない。図１４では、上面視におけるエッジ終端構造部９０の全体に、通過領域１０６およびヘリウム濃度ピーク１４１が設けられていない例を示している。他の例では、エッジ終端構造部９０のうち、活性部１２０に近い側の端部には、通過領域１０６およびヘリウム濃度ピーク１４１が設けられていてもよい。つまり、半導体基板１０の外周端１４０と接する領域には、通過領域１０６およびヘリウム濃度ピーク１４１が設けられていない。本例では、外周端１４０の近傍には、ヘリウム濃度ピーク１４１が設けられないので、外周端１４０の近傍に欠陥が形成されるのを抑制できる。このため、外周端１４０におけるリークの増大を抑制できる。 In this example, the passage region 106 and the helium concentration peak 141 are not provided in at least a partial region of the edge termination structure portion 90 in a top view. FIG. 14 shows an example in which the passage region 106 and the helium concentration peak 141 are not provided in the entire edge termination structure portion 90 in a top view. In another example, the passage region 106 and the helium concentration peak 141 may be provided at the end portion of the edge termination structure portion 90 near the active portion 120. That is, the passage region 106 and the helium concentration peak 141 are not provided in the region in contact with the outer peripheral edge 140 of the semiconductor substrate 10. In this example, since the helium concentration peak 141 is not provided near the outer peripheral edge 140, it is possible to suppress the formation of defects near the outer peripheral edge 140. Therefore, it is possible to suppress an increase in leakage at the outer peripheral edge 140.
　すなわち、本例のベースドーピング領域１８０は、半導体基板１０の外周端１４０と接する領域に設けられる。本例のベースドーピング領域１８０は、上面視で、エッジ終端構造部９０の少なくとも一部の領域に設けられる。さらにベースドーピング領域１８０は、上面視で、エッジ終端構造部９０の全体と、境界部７２に設けられてよい。 That is, the base doping region 180 of this example is provided in a region in contact with the outer peripheral edge 140 of the semiconductor substrate 10. The base doping region 180 of this example is provided in at least a part of the region of the edge termination structure 90 in a top view. Further, the base doping region 180 may be provided on the entire edge termination structure 90 and the boundary 72 in a top view.
　なお境界部７２の通過領域１０６の配置は、エッジ終端構造部９０と同一であってよく、トランジスタ部７０と同一であってよく、ダイオード部８０と同一であってもよい。図１４では、境界部７２に通過領域１０６を設けていない例を示している。 The arrangement of the passage region 106 of the boundary portion 72 may be the same as that of the edge termination structure portion 90, that of the transistor portion 70, or that of the diode portion 80. FIG. 14 shows an example in which the passage area 106 is not provided in the boundary portion 72.
　図１５は、通過領域１０６の他の配置例を示す図である。本例の通過領域１０６は、深さ方向における配置が、図１３に示した通過領域１０６と同一であり、上面視における配置が、図１４に示した通過領域１０６と同一である。つまり、エッジ終端構造部９０には通過領域１０６が設けられていない。また、トランジスタ部７０およびダイオード部８０には、半導体基板１０の下面２３から、半導体基板１０の深さ方向の中央近傍まで、通過領域１０６が設けられている。 FIG. 15 is a diagram showing another arrangement example of the passage area 106. The passage area 106 of the present example has the same arrangement in the depth direction as the passage area 106 shown in FIG. 13, and the arrangement in top view is the same as the passage area 106 shown in FIG. 14. That is, the passage region 106 is not provided in the edge termination structure portion 90. Further, the transistor portion 70 and the diode portion 80 are provided with a passage region 106 from the lower surface 23 of the semiconductor substrate 10 to the vicinity of the center in the depth direction of the semiconductor substrate 10.
　本例のベースドーピング領域１８０は、境界部７２とエッジ終端構造部９０において、上面２１からバッファ領域２０まで形成される。また、活性部においては、ヘリウム濃度ピーク１４１より上面２１側のドリフト領域１８に、ベースドーピング領域１８０が形成される。ヘリウム濃度ピーク１４１よりも上面２１側では、本例のベースドーピング領域１８０は、上面視で、半導体基板１０の全面に設けられる。 The base doping region 180 of this example is formed from the upper surface 21 to the buffer region 20 at the boundary 72 and the edge termination structure 90. Further, in the active portion, the base doping region 180 is formed in the drift region 18 on the upper surface 21 side of the helium concentration peak 141. On the upper surface 21 side of the helium concentration peak 141, the base doping region 180 of this example is provided on the entire surface of the semiconductor substrate 10 in a top view.
　図１６Ａは、通過領域１０６の他の配置例を示す図である。本例においては、上面視におけるダイオード部８０の少なくとも一部に通過領域１０６およびヘリウム濃度ピーク１４１が設けられていない点で、図１２から図１５における例と相違する。他の構造は、図１２から図１５において説明した例と同一である。 FIG. 16A is a diagram showing another arrangement example of the passage area 106. This example is different from the examples in FIGS. 12 to 15 in that the passing region 106 and the helium concentration peak 141 are not provided in at least a part of the diode portion 80 in a top view. The other structure is the same as the example described in FIGS.
　図１６Ａでは、上面視におけるダイオード部８０の全体に通過領域１０６およびヘリウム濃度ピーク１４１が設けられていない例を示している。すなわち、ベースドーピング領域１８０を、上面視でダイオード部８０の全体に設けている。また、境界部７２とエッジ終端構造部９０の全体にも、ベースドーピング領域１８０を設けている。他の例では、ダイオード部８０のうち、トランジスタ部７０と接する端部には、通過領域１０６およびヘリウム濃度ピーク１４１が設けられていてもよい。トランジスタ部７０とダイオード部８０とで、通過領域１０６の配置を異ならせることで、ダイオード部８０とトランジスタ部７０のドーピング濃度の分布を適宜異ならせることができる。 FIG. 16A shows an example in which the passing region 106 and the helium concentration peak 141 are not provided in the entire diode portion 80 in a top view. That is, the base doping region 180 is provided on the entire diode portion 80 in a top view. Further, the base doping region 180 is also provided on the entire boundary portion 72 and the edge termination structure portion 90. In another example, the passage region 106 and the helium concentration peak 141 may be provided at the end portion of the diode portion 80 that is in contact with the transistor portion 70. By making the arrangement of the passage region 106 different between the transistor section 70 and the diode section 80, the distributions of the doping concentrations of the diode section 80 and the transistor section 70 can be made different as appropriate.
　図１６Ｂは、通過領域１０６の他の配置例を示す図である。図１６Ｂは、活性部において、通過領域１０６とベースドーピング領域１８０を、図１６Ａと逆に形成した構成である。ダイオード部８０に通過領域１０６を形成することで、逆回復時の空間電荷領域の拡張を抑制し、逆回復時の波形振動を抑える。一方、トランジスタ部７０をベースドーピング領域１８０とすることで、例えば短絡発生時に空間電荷領域の拡張を促して正孔の注入を促進させ、短絡破壊を抑制する。 FIG. 16B is a diagram showing another arrangement example of the passage area 106. 16B shows a configuration in which the pass-through region 106 and the base doping region 180 are formed in the active portion in the opposite manner to FIG. 16A. By forming the passage region 106 in the diode portion 80, the expansion of the space charge region at the time of reverse recovery is suppressed and the waveform vibration at the time of reverse recovery is suppressed. On the other hand, by using the transistor part 70 as the base doping region 180, for example, when a short circuit occurs, expansion of the space charge region is promoted, injection of holes is promoted, and short circuit breakdown is suppressed.
　図１７Ａは、通過領域１０６の他の配置例を示す図である。本例の通過領域１０６は、深さ方向における配置が、図１３に示した通過領域１０６と同一であり、上面視における配置が、図１６Ａに示した通過領域１０６と同一である。つまり、ダイオード部８０には通過領域１０６が設けられていない。トランジスタ部７０には、半導体基板１０の下面２３から、半導体基板１０の深さ方向の中央近傍まで、通過領域１０６が設けられている。また、図１７Ａの例においては、ヘリウム濃度ピーク１４１をトレンチ部底面から下面２３側へ後退させ、ヘリウム濃度ピーク１４１よりも上面２１側でベースドーピング領域１８０を上面視の全面に形成している。 FIG. 17A is a diagram showing another arrangement example of the passage area 106. The passage area 106 in this example has the same arrangement in the depth direction as the passage area 106 shown in FIG. 13, and the arrangement in a top view is the same as the passage area 106 shown in FIG. 16A. That is, the diode region 80 is not provided with the passage region 106. In the transistor portion 70, a passage region 106 is provided from the lower surface 23 of the semiconductor substrate 10 to the vicinity of the center of the semiconductor substrate 10 in the depth direction. Further, in the example of FIG. 17A, the helium concentration peak 141 is made to recede from the bottom surface of the trench portion to the lower surface 23 side, and the base doping region 180 is formed on the entire upper surface side on the upper surface 21 side with respect to the helium concentration peak 141.
　図１７Ｂは、通過領域１０６の他の配置例を示す図である。図１７Ｂの例は、活性部において、通過領域１０６とベースドーピング領域１８０を、図１７Ａと逆に形成した構成である。図１７Ｂの例においても、図１６Ｂと同様の効果を奏する。 FIG. 17B is a diagram showing another arrangement example of the passage area 106. The example of FIG. 17B has a configuration in which the passage region 106 and the base doping region 180 are formed in the active portion in the opposite manner to that of FIG. 17A. Also in the example of FIG. 17B, the same effect as that of FIG. 16B is obtained.
　図１４から図１７Ｂにおいて説明した通過領域１０６を形成するには、後述する第２注入段階Ｓ１９０２において、ヘリウムイオンの注入を上面視で選択的に行う。例えば、図１４から図１７Ｂに示したフォトレジスト膜２００を用いて、選択的なヘリウムイオン注入を行うことができる。 To form the passage region 106 described with reference to FIGS. 14 to 17B, helium ions are selectively implanted in a top view in a second implantation step S1902 described later. For example, selective helium ion implantation can be performed using the photoresist film 200 shown in FIGS. 14 to 17B.
　この場合、第２注入段階Ｓ１９０２の前に、半導体基板１０の下面２３の一部に、所定の厚みのフォトレジスト膜２００を選択的に形成する。フォトレジスト膜２００の厚みは、ヘリウムイオンを遮蔽できる厚みである。 In this case, prior to the second implantation step S1902, a photoresist film 200 having a predetermined thickness is selectively formed on a part of the lower surface 23 of the semiconductor substrate 10. The thickness of the photoresist film 200 is a thickness that can shield helium ions.
　フォトレジスト膜２００を形成した後、第２注入段階Ｓ１９０２を行う。フォトレジスト膜２００を形成した領域は、フォトレジスト膜２００によりヘリウムイオンが遮蔽される。このため、フォトレジスト膜２００で覆われた半導体基板１０の領域にはヘリウムイオンが侵入しない。フォトレジスト膜２００を形成していない領域は、加速エネルギーに応じて、第２の深さ位置Ｚ２にヘリウムイオンが注入される。なお、図１４、図１５、図１６Ａ、図１６Ｂ、図１７Ａおよび図１７Ｂの各例において、フォトレジスト膜２００は、半導体基板１０の下面２３に接して形成される。フォトレジスト膜２００を形成する段階においては、下面２３にコレクタ電極５４が設けられていない。 After forming the photoresist film 200, a second implantation step S1902 is performed. Helium ions are shielded by the photoresist film 200 in the region where the photoresist film 200 is formed. Therefore, helium ions do not enter the region of the semiconductor substrate 10 covered with the photoresist film 200. Helium ions are implanted into the second depth position Z2 in the region where the photoresist film 200 is not formed, depending on the acceleration energy. In each of FIGS. 14, 15, 16A, 16B, 17A, and 17B, the photoresist film 200 is formed in contact with the lower surface 23 of the semiconductor substrate 10. At the stage of forming the photoresist film 200, the collector electrode 54 is not provided on the lower surface 23.
　図１７Ｃは、ヘリウムイオンを半導体基板１０に侵入させないための、フォトレジスト膜２００の最小膜厚Ｍを説明する図である。図１７Ｃは、ヘリウムイオンの飛程Ｒｐに対する、膜厚Ｍを示している。 FIG. 17C is a diagram for explaining the minimum film thickness M of the photoresist film 200 for preventing helium ions from entering the semiconductor substrate 10. FIG. 17C shows the film thickness M with respect to the range Rp of helium ions.
　本例のヘリウムイオンは、フォトレジスト膜２００以外のアブソーバーを介さずに、加速器から半導体基板１０に注入されてよい。ヘリウムイオンの飛程Ｒｐは、加速器における加速エネルギーによって一義的に定まる。 The helium ions of this example may be injected from the accelerator into the semiconductor substrate 10 without passing through an absorber other than the photoresist film 200. The range Rp of helium ions is uniquely determined by the acceleration energy in the accelerator.
　また、ヘリウムイオンを遮蔽できるフォトレジスト膜２００の最小膜厚Ｍは、ヘリウムイオンの加速エネルギーによって定まる。このため、フォトレジスト膜２００の最小膜厚Ｍは、ヘリウムイオンの飛程Ｒｐであらわすことができる。図１７Ｃは、ヘリウムイオンの飛程Ｒｐと、膜厚Ｍとの関係を３点計測し、直線で近似した図である。膜厚Ｍ（μｍ）と飛程Ｒｐ（μｍ）との関係は、下式で表すことができる。
　Ｍ＝１．７６×Ｒｐ＋１２．３２
　フォトレジスト膜２００の厚みは、上式で示される最小膜厚Ｍと同一か、より大きいことが好ましい。 The minimum film thickness M of the photoresist film 200 that can shield helium ions is determined by the acceleration energy of helium ions. Therefore, the minimum thickness M of the photoresist film 200 can be represented by the range Rp of helium ions. FIG. 17C is a diagram in which the relationship between the range Rp of helium ions and the film thickness M is measured at three points and is approximated by a straight line. The relationship between the film thickness M (μm) and the range Rp (μm) can be expressed by the following formula.
M=1.76×Rp+12.32
The thickness of the photoresist film 200 is preferably equal to or larger than the minimum film thickness M shown by the above equation.
　他の例として、ヘリウムイオンは、フォトレジスト膜２００以外のアブソーバーを介して、加速器から半導体基板１０に注入されてもよい。ヘリウムイオンの飛程Ｒｐは、加速器における加速エネルギーと、ヘリウムイオンの注入方向に沿ったアブソーバーの厚さによって定まる。 As another example, helium ions may be injected into the semiconductor substrate 10 from the accelerator via an absorber other than the photoresist film 200. The range Rp of helium ions is determined by the acceleration energy in the accelerator and the thickness of the absorber along the implantation direction of helium ions.
　図１８Ａは、通過領域１０６の他の配置例を示す図である。本例では、エッジ終端構造部９０に設けられた通過領域１０６の深さ方向における幅Ｔ５は、活性部１２０（本例ではダイオード部８０）に設けられた通過領域１０６の深さ方向における幅Ｔ４よりも短い。 FIG. 18A is a diagram showing another arrangement example of the passage area 106. In this example, the width T5 in the depth direction of the passage region 106 provided in the edge termination structure portion 90 is the width T4 in the depth direction of the passage region 106 provided in the active portion 120 (the diode portion 80 in this example). Shorter than.
　ダイオード部８０においては、ヘリウム濃度ピーク１４１は、ダミートレンチ部３０の底部と、半導体基板１０の上面２１との間に配置されていてよい。エッジ終端構造部９０においては、ヘリウム濃度ピーク１４１は、ガードリング９２と、半導体基板１０の下面２３との間に配置されていてよい。エッジ終端構造部９０における通過領域１０６の幅Ｔ５は、半導体基板１０の厚さＴの半分より大きくてよい。 In the diode section 80, the helium concentration peak 141 may be arranged between the bottom of the dummy trench section 30 and the upper surface 21 of the semiconductor substrate 10. In the edge termination structure portion 90, the helium concentration peak 141 may be arranged between the guard ring 92 and the lower surface 23 of the semiconductor substrate 10. The width T5 of the passage region 106 in the edge termination structure 90 may be larger than half the thickness T of the semiconductor substrate 10.
　また、トランジスタ部７０に設けられた通過領域１０６の深さ方向における幅Ｔ３は、ダイオード部８０に設けられた通過領域１０６の深さ方向における幅Ｔ４よりも短くてよい。すなわち、トランジスタ部７０においては、ベースドーピング領域１８０が、トレンチ部深さよりも深く形成される。つまりトランジスタ部７０のヘリウム濃度ピーク１４１は、トレンチ部の底面よりも下面２３側に位置する。トランジスタ部７０においては、ヘリウム濃度ピーク１４１は、ゲートトレンチ部４０の底部と、半導体基板１０の下面２３との間に配置されていてよい。幅Ｔ３は、幅Ｔ５と同一であってよく、幅Ｔ５より大きくてよく、幅Ｔ５より小さくてもよい。トランジスタ部７０における通過領域１０６の幅Ｔ３は、半導体基板１０の厚さＴの半分より大きくてよい。これにより、トランジスタ部７０においてチャネルが形成されるベース領域１４と、ヘリウム濃度ピーク１４１とを離して配置できる。このため、チャネル近傍における欠陥の増大を抑制できる。 The width T3 of the passage region 106 provided in the transistor portion 70 in the depth direction may be shorter than the width T4 of the passage region 106 provided in the diode portion 80 in the depth direction. That is, in the transistor part 70, the base doping region 180 is formed deeper than the depth of the trench part. That is, the helium concentration peak 141 of the transistor part 70 is located closer to the lower surface 23 side than the bottom surface of the trench part. In the transistor part 70, the helium concentration peak 141 may be arranged between the bottom part of the gate trench part 40 and the lower surface 23 of the semiconductor substrate 10. The width T3 may be the same as the width T5, may be larger than the width T5, or may be smaller than the width T5. The width T3 of the passage region 106 in the transistor portion 70 may be larger than half the thickness T of the semiconductor substrate 10. As a result, the base region 14 in which a channel is formed in the transistor section 70 and the helium concentration peak 141 can be arranged apart from each other. Therefore, it is possible to suppress an increase in defects near the channel.
　境界部７２における通過領域１０６は、エッジ終端構造部９０における通過領域１０６と同一の構造を有してよく、トランジスタ部７０における通過領域１０６と同一の構造を有してよく、ダイオード部８０における通過領域１０６と同一の構造を有してもよい。また、図１８Ａの例において、トランジスタ部７０に通過領域１０６が設けられていなくてもよい。ダイオード部８０に通過領域１０６が設けられていなくてもよい。エッジ終端構造部９０に通過領域１０６が設けられていなくてもよい。境界部７２に通過領域１０６が設けられていなくてもよい。 The pass region 106 at the boundary portion 72 may have the same structure as the pass region 106 in the edge termination structure portion 90, may have the same structure as the pass region 106 in the transistor portion 70, and may have the pass portion in the diode portion 80. It may have the same structure as the region 106. Further, in the example of FIG. 18A, the passage region 106 may not be provided in the transistor unit 70. The passing region 106 may not be provided in the diode portion 80. The passage region 106 may not be provided in the edge termination structure portion 90. The passage area 106 may not be provided in the boundary portion 72.
　図１８Ｂは、通過領域１０６の他の配置例を示す図である。本例では、エッジ終端構造部９０に設けられた通過領域１０６の深さ方向における幅Ｔ５は、活性部１２０（本例ではトランジスタ部７０）に設けられた通過領域１０６の深さ方向における幅Ｔ３よりも短い。 FIG. 18B is a diagram showing another arrangement example of the passage area 106. In this example, the width T5 in the depth direction of the passage region 106 provided in the edge termination structure portion 90 is the width T3 in the depth direction of the passage region 106 provided in the active portion 120 (transistor portion 70 in this example). Shorter than.
　トランジスタ部７０においては、ヘリウム濃度ピーク１４１は、ゲートトレンチ部４０の底部と、半導体基板１０の上面２１との間に配置されていてよい。エッジ終端構造部９０における通過領域１０６およびヘリウム濃度ピーク１４１の構造は、図１８Ａの例と同様である。 In the transistor section 70, the helium concentration peak 141 may be arranged between the bottom of the gate trench section 40 and the upper surface 21 of the semiconductor substrate 10. The structures of the passage region 106 and the helium concentration peak 141 in the edge termination structure portion 90 are similar to those in the example of FIG. 18A.
　ダイオード部８０に設けられた通過領域１０６の深さ方向における幅Ｔ４は、トランジスタ部７０に設けられた通過領域１０６の深さ方向における幅Ｔ３よりも短くてよい。すなわち、ダイオード部８０においては、ベースドーピング領域１８０が、トレンチ部深さよりも深く形成される。つまりダイオード部８０のヘリウム濃度ピーク１４１は、トレンチ部の底面よりも下面２３側に位置する。ダイオード部８０においては、ヘリウム濃度ピーク１４１は、ダミートレンチ部３０の底部と、半導体基板１０の下面２３との間に配置されていてよい。幅Ｔ４は、幅Ｔ５と同一であってよく、幅Ｔ５より大きくてよく、幅Ｔ５より小さくてもよい。ダイオード部８０における通過領域１０６の幅Ｔ４は、半導体基板１０の厚さＴの半分より大きくてよい。 The width T4 in the depth direction of the passage region 106 provided in the diode portion 80 may be shorter than the width T3 in the depth direction of the passage region 106 provided in the transistor portion 70. That is, in the diode portion 80, the base doping region 180 is formed deeper than the trench portion depth. That is, the helium concentration peak 141 of the diode portion 80 is located closer to the lower surface 23 side than the bottom surface of the trench portion. In the diode section 80, the helium concentration peak 141 may be arranged between the bottom of the dummy trench section 30 and the lower surface 23 of the semiconductor substrate 10. The width T4 may be the same as the width T5, larger than the width T5, or smaller than the width T5. The width T4 of the passage region 106 in the diode portion 80 may be larger than half the thickness T of the semiconductor substrate 10.
　境界部７２における通過領域１０６は、エッジ終端構造部９０における通過領域１０６と同一の構造を有してよく、トランジスタ部７０における通過領域１０６と同一の構造を有してよく、ダイオード部８０における通過領域１０６と同一の構造を有してもよい。また、図１８Ｂの例において、トランジスタ部７０に通過領域１０６が設けられていなくてもよい。ダイオード部８０に通過領域１０６が設けられていなくてもよい。エッジ終端構造部９０に通過領域１０６が設けられていなくてもよい。境界部７２に通過領域１０６が設けられていなくてもよい。 The pass region 106 at the boundary portion 72 may have the same structure as the pass region 106 in the edge termination structure portion 90, may have the same structure as the pass region 106 in the transistor portion 70, and may have the pass portion in the diode portion 80. It may have the same structure as the region 106. Further, in the example of FIG. 18B, the passage region 106 may not be provided in the transistor unit 70. The passing region 106 may not be provided in the diode portion 80. The passage region 106 may not be provided in the edge termination structure portion 90. The passage area 106 may not be provided in the boundary portion 72.
　図１２から図１８Ｂに示したように、通過領域１０６の構造を調整することで、トランジスタ部７０、ダイオード部８０およびエッジ終端構造部９０におけるドナー濃度分布を容易に調整できる。通過領域１０６の構造は、図１２から図１８Ｂに示した例に限定されない。 As shown in FIGS. 12 to 18B, the donor concentration distribution in the transistor section 70, the diode section 80, and the edge termination structure section 90 can be easily adjusted by adjusting the structure of the passage region 106. The structure of the passage area 106 is not limited to the examples shown in FIGS. 12 to 18B.
　図１９は、半導体装置１００の製造方法において、通過領域１０６を形成する工程を示す図である。通過領域１０６を形成する場合、第１注入段階Ｓ１９００において、半導体基板１０の下面２３から第１の深さＺ１に水素イオンを注入する。また、第２注入段階Ｓ１９０２において、半導体基板１０の下面２３から第２の深さＺ２にヘリウムイオンを注入することで通過領域１０６を形成する。第１注入段階Ｓ１９００および第２注入段階Ｓ１９０２は、いずれを先に行ってもよい。 FIG. 19 is a diagram showing a step of forming the passage region 106 in the method of manufacturing the semiconductor device 100. When forming the passage region 106, hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 to the first depth Z1 in the first implantation step S1900. In addition, in the second implantation step S1902, the passage region 106 is formed by implanting helium ions from the lower surface 23 of the semiconductor substrate 10 to the second depth Z2. Either the first injection step S1900 or the second injection step S1902 may be performed first.
　なお、第１注入段階Ｓ１９００を先に行う場合において、第１注入段階Ｓ１９００と第２注入段階Ｓ１９０２との間に熱処理を行うと、通過領域１０６のドナー濃度を高めることができない場合がある。つまり、通過領域１０６を形成する前に熱処理を行うと、第１注入段階Ｓ１９００で注入した水素が通過領域１０６の結晶欠陥と結合できずに、半導体基板１０の外部に抜けてしまう場合がある。このため、第１注入段階Ｓ１９００と第２注入段階Ｓ１９０２との間では、熱処理を行わないことが好ましい。熱処理は、例えば３００℃以上で半導体基板１０を加熱する処理である。 In the case where the first implantation step S1900 is performed first, if the heat treatment is performed between the first implantation step S1900 and the second implantation step S1902, the donor concentration in the passage region 106 may not be increased. That is, if the heat treatment is performed before forming the passage region 106, the hydrogen implanted in the first implantation step S1900 may not be combined with the crystal defects in the passage region 106 and may escape to the outside of the semiconductor substrate 10. Therefore, it is preferable that the heat treatment is not performed between the first implantation step S1900 and the second implantation step S1902. The heat treatment is, for example, a treatment of heating the semiconductor substrate 10 at 300° C. or higher.
　第１注入段階Ｓ１９００および第２注入段階Ｓ１９０２の後に、拡散段階Ｓ１９０４を行う。拡散段階Ｓ１９０４においては、半導体基板１０を熱処理して、第１の深さＺ１に注入された水素を通過領域１０６に拡散させる。拡散段階Ｓ１９０４においては、半導体基板１０を３００℃以上に加熱してよい。加熱温度は、３５０℃以上であってもよい。拡散段階Ｓ１９０４においては、半導体基板１０を１時間以上加熱してよく、３時間以上加熱してもよい。 A diffusion step S1904 is performed after the first injection step S1900 and the second injection step S1902. In the diffusion step S1904, the semiconductor substrate 10 is heat-treated to diffuse the hydrogen implanted into the first depth Z1 into the passage region 106. In the diffusion step S1904, the semiconductor substrate 10 may be heated to 300° C. or higher. The heating temperature may be 350° C. or higher. In the diffusion step S1904, the semiconductor substrate 10 may be heated for 1 hour or longer, or may be heated for 3 hours or longer.
　拡散段階Ｓ１９０４において水素を拡散させることで、通過領域１０６における結晶欠陥と水素とが結合してドナー化する。これにより、通過領域１０６におけるドナー濃度を高めることができる。拡散段階Ｓ１９０４においては、通過領域１０６のドナー濃度の最小値が、第１注入段階Ｓ１９００および第２注入段階Ｓ１９０２の前の半導体基板１０のドナー濃度（ベースドーピング濃度）よりも高くなることが好ましい。つまり、通過領域１０６の全体において、ドナー濃度がベースドーピング濃度よりも高くなることが好ましい。 By diffusing hydrogen in the diffusion step S1904, the crystal defects in the passage region 106 and hydrogen are combined to form a donor. Thereby, the donor concentration in the passage region 106 can be increased. In the diffusion step S1904, the minimum donor concentration of the passage region 106 is preferably higher than the donor concentration (base doping concentration) of the semiconductor substrate 10 before the first implantation step S1900 and the second implantation step S1902. That is, it is preferable that the donor concentration be higher than the base doping concentration in the entire passage region 106.
　通過領域１０６の全体におけるドナー濃度を高めるには、第１の深さ位置Ｚ１に注入した水素が、第２の深さ位置Ｚ２の近傍まで拡散することが好ましい。第１注入段階Ｓ１９００において、第１の深さ位置Ｚ１に注入する水素のドーズ量を調整することで、第２の深さ位置Ｚ２の近傍まで、十分な水素を拡散させることができる。第１注入段階Ｓ１９００においては、通過領域１０６のドナー濃度の最小値が、ベースドーピング濃度よりも高くなるように、水素のドーズ量を定めることが好ましい。 In order to increase the donor concentration in the entire passage region 106, it is preferable that the hydrogen injected at the first depth position Z1 diffuses to the vicinity of the second depth position Z2. In the first implantation step S1900, by adjusting the dose amount of hydrogen implanted at the first depth position Z1, sufficient hydrogen can be diffused to the vicinity of the second depth position Z2. In the first implantation step S1900, the dose amount of hydrogen is preferably determined so that the minimum value of the donor concentration in the passage region 106 is higher than the base doping concentration.
　第１注入段階Ｓ１９００で、ヘリウムイオンの停止領域（飛程Ｒｐ）の近傍に、水素イオンを注入してもよい。第１注入段階の水素イオン注入は、第２注入段階Ｓ１９０２のヘリウムイオン注入の前に行ってよいし、後に行ってもよい。ヘリウムイオンの停止領域近傍には、イオン注入ダメージ（ディスオーダー）も局在する。ディスオーダーにはダングリングボンドが多く存在する。第１注入段階Ｓ１９００で、ヘリウムイオンの停止領域の近傍に水素イオンも注入することで、ディスオーダーのダングリングボンドを水素が終端し、ディスオーダーを低減できる。 In the first implantation step S1900, hydrogen ions may be implanted near the helium ion stop region (range Rp). The hydrogen ion implantation in the first implantation step may be performed before or after the helium ion implantation in the second implantation step S1902. Ion implantation damage (disorder) is also localized near the helium ion stop region. There are many dangling bonds in disorder. In the first implantation step S1900, hydrogen ions are also implanted in the vicinity of the helium ion stop region, whereby hydrogen terminates disordered dangling bonds, and disorder can be reduced.
　バッファ領域２０に、図９等に示す複数の水素ドナーのピーク２４を形成する場合、第１注入段階Ｓ１９００における水素イオン注入の他に、水素イオン注入を複数回行ってよい。ピーク２４を形成するための複数の水素イオン注入は、第１注入段階Ｓ１９００で行ってよい。つまり、第１注入段階Ｓ１９００を複数回行ってよい。 When forming a plurality of hydrogen donor peaks 24 shown in FIG. 9 and the like in the buffer region 20, hydrogen ion implantation may be performed multiple times in addition to the hydrogen ion implantation in the first implantation step S1900. The plurality of hydrogen ion implantations for forming the peak 24 may be performed in the first implantation step S1900. That is, the first injection step S1900 may be performed multiple times.
　図２０から図２６は、第１の深さＺ１に注入する水素イオンのドーズ量（第１ドーズ量と称する）を決定する方法を説明する図である。本例の第１注入段階Ｓ１９００では、半導体基板１０における水素の拡散係数と、第２の深さＺ２の位置（つまり、第１の深さ位置Ｚ１に注入した水素が拡散すべき距離）から定まる最小ドーズ量以上のドーズ量で、水素を注入する。 20 to 26 are diagrams for explaining a method of determining the dose amount of hydrogen ions to be implanted at the first depth Z1 (referred to as a first dose amount). In the first implantation step S1900 of this example, it is determined from the diffusion coefficient of hydrogen in the semiconductor substrate 10 and the position of the second depth Z2 (that is, the distance at which the hydrogen implanted at the first depth position Z1 should diffuse). Hydrogen is implanted at a dose amount equal to or higher than the minimum dose amount.
　図２０は、拡散段階Ｓ１９０４の後の半導体基板１０における、キャリア濃度分布の一例を示す図である。図２０のキャリア濃度分布は、例えば拡がり抵抗測定（Ｓｐｒｅａｄ　Ｒｅｓｉｓｔａｎｃｅ　Ｐｒｏｆｉｌｉｎｇ）により取得できる。図２０から図２６の各図において、半導体基板１０の下面２３を、深さ（μｍ）の基準位置（０μｍ）とする。また、第１の深さＺ１は、１０μｍ以下である。第１の深さＺ１を０μｍとして扱ってもよい。 FIG. 20 is a diagram showing an example of carrier concentration distribution in the semiconductor substrate 10 after the diffusion step S1904. The carrier concentration distribution of FIG. 20 can be acquired by, for example, spread resistance measurement (Spread Resistance Profiling). In each of FIGS. 20 to 26, the lower surface 23 of the semiconductor substrate 10 is set as a reference position (0 μm) of depth (μm). Further, the first depth Z1 is 10 μm or less. The first depth Z1 may be treated as 0 μm.
　図２０においては、５種類の半導体基板１０のキャリア濃度分布を示している。第１の例１６１、第２の例１６２および第３の例１６３は、第１の深さＺ１に水素イオンを注入し、第２の深さＺ２にヘリウムイオンを注入した例である。第４の例１６４および第５の例１６５は、第２の深さＺ２にヘリウムイオンを注入し、第１の深さＺ１には水素を注入していない例である。各例において、第２の深さＺ２へのヘリウムイオンのドーズ量（第２のドーズ量と称する）を１×１０１３／ｃｍ２とした。また、第２の深さＺ２へのヘリウムイオンの飛程を１００μｍ、加速エネルギーを４．０Ｍｅｖとした。ヘリウムイオンの飛程は、加速エネルギーによって調整してもよいし、アルミニウムアブソーバー等で調整してもよい。 In FIG. 20, carrier concentration distributions of five types of semiconductor substrates 10 are shown. The first example 161, the second example 162, and the third example 163 are examples in which hydrogen ions are implanted into the first depth Z1 and helium ions are implanted into the second depth Z2. The fourth example 164 and the fifth example 165 are examples in which helium ions are implanted into the second depth Z2 and hydrogen is not implanted into the first depth Z1. In each example, the dose amount of helium ions to the second depth Z2 (referred to as the second dose amount) was set to 1×10 13 /cm 2 . Further, the range of helium ions to the second depth Z2 was 100 μm, and the acceleration energy was 4.0 Mev. The range of helium ions may be adjusted by acceleration energy, or may be adjusted by an aluminum absorber or the like.
　第１の例１６１、第２の例１６２および第３の例１６３においては、第１の深さＺ１への水素イオンの加速エネルギーを４００ｋｅＶとした。第１の例１６１においては、第１のドーズ量を１×１０１５／ｃｍ２とした。第２の例１６２においては、第１のドーズ量を３×１０１４／ｃｍ２とした。第３の例１６３においては、第１のドーズ量を１×１０１４／ｃｍ２とした。 In the first example 161, the second example 162, and the third example 163, the acceleration energy of hydrogen ions to the first depth Z1 was 400 keV. In the first example 161, the first dose amount was set to 1×10 15 /cm 2 . In the second example 162, the first dose amount was 3×10 14 /cm 2 . In the third example 163, the first dose amount was set to 1×10 14 /cm 2 .
　水素イオンを注入した後、各例の半導体基板１０を、同一のアニール炉で、３７０℃、５時間アニールした。ただし、第５の例１６５はアニールしていない。図２０は、アニール後のキャリア濃度分布である。各例においてアニール前は、通過領域１０６（半導体基板１０の下面２３から第２の深さ位置Ｚ２までの範囲）に結晶欠陥が形成される。このため、通過領域１０６のキャリア濃度は低下する。 After implanting hydrogen ions, the semiconductor substrate 10 of each example was annealed in the same annealing furnace at 370° C. for 5 hours. However, the fifth example 165 is not annealed. FIG. 20 is a carrier concentration distribution after annealing. In each example, before annealing, crystal defects are formed in the passage region 106 (the range from the lower surface 23 of the semiconductor substrate 10 to the second depth position Z2). Therefore, the carrier concentration in the passage region 106 is reduced.
　アニール後においては、水素が結晶欠陥と結合してドナー化することで、キャリア濃度が上昇する。ただし、第４の例１６４においては、第１の深さＺ１に水素を注入していないので、キャリア濃度がほとんど上昇しない。第１の例１６１、第２の例１６２および第３の例１６３に示すように、第１のドーズ量が増加するほど、通過領域１０６のキャリア濃度が上昇する。また、第１のドーズ量が増加するほど、第１の深さＺ１から遠い領域まで、ベースドーピング濃度よりもドナー濃度が高い領域が広がっている。つまり、第１のドーズ量が増加するほど、第１の深さＺ１からの水素拡散が、遠い領域まで到達している。 After annealing, hydrogen combines with crystal defects and becomes a donor, which increases the carrier concentration. However, in the fourth example 164, since hydrogen is not injected to the first depth Z1, the carrier concentration hardly increases. As shown in the first example 161, the second example 162, and the third example 163, as the first dose amount increases, the carrier concentration in the passage region 106 increases. Further, as the first dose amount increases, a region having a donor concentration higher than the base doping concentration spreads from the first depth Z1 to a region farther from the first depth Z1. That is, as the first dose amount increases, hydrogen diffusion from the first depth Z1 reaches a farther region.
　第１のドーズ量をＱ、第１の深さＺ１からの水素の拡散深さをｘ（ｘ１、ｘ２、ｘ３）（ｃｍ）、水素の拡散係数をＤ（ｃｍ２／ｓ）、拡散時間をｔ、半導体基板１０のベースドーピング濃度をＣ０（ａｔｏｍｓ／ｃｍ３）とすると、これらの関係は、下の式（１）であらわされる。
　
　式（１）は、拡散方程式の解から算出する値である。拡散方程式を、水素の総量が一定であるという境界条件で解いたときの解は、ガウス分布となる。得られたガウス分布の解において、濃度Ｃ（ｘ、ｔ）がベースドーピング濃度Ｃ０と一致するときのｘが、式（１）である。
Figure JPOXMLDOC01-appb-M000001
 The first dose amount is Q, the diffusion depth of hydrogen from the first depth Z1 is x(x1, x2, x3) (cm), the diffusion coefficient of hydrogen is D (cm 2 /s), and the diffusion time is When t is the base doping concentration of the semiconductor substrate 10 and C 0 (atoms/cm 3 ), the relationship between them is expressed by the following equation (1).

Expression (1) is a value calculated from the solution of the diffusion equation. When the diffusion equation is solved under the boundary condition that the total amount of hydrogen is constant, the solution has a Gaussian distribution. In the obtained Gaussian distribution solution, x when the concentration C(x, t) matches the base doping concentration C 0 is the equation (1).
Figure JPOXMLDOC01-appb-M000001
　式（１）から、第１の例１６１、第２の例１６２、第３の例１６３における水素の拡散係数Ｄを数値的に算出できる。各例における拡散深さｘは、図２０のプロファイル形状から決定してよい。例えば拡散深さｘは、第１の深さ位置Ｚ１から、キャリア濃度の谷の部分の最初の変曲点までの距離を用いることができる。また、拡散深さｘは、第１の深さ位置Ｚ１から、キャリア濃度がベースドーピング濃度を最初に下回る位置までの距離を用いてもよい。 The hydrogen diffusion coefficient D in the first example 161, the second example 162, and the third example 163 can be calculated numerically from the equation (1). The diffusion depth x in each example may be determined from the profile shape of FIG. For example, as the diffusion depth x, the distance from the first depth position Z1 to the first inflection point in the valley portion of the carrier concentration can be used. As the diffusion depth x, the distance from the first depth position Z1 to the position where the carrier concentration first falls below the base doping concentration may be used.
　なお、第２の深さＺ２に水素イオンを注入した場合に形成される結晶欠陥は、点欠陥、転位などの様々な欠陥である。特に点欠陥のうち、空孔、複空孔の空孔系欠陥が形成される。この場合、結晶欠陥の濃度は、第２の深さＺ２から、イオン注入面（半導体基板１０の下面２３）に若干近づいた位置にピークを有する。 The crystal defects formed when hydrogen ions are implanted to the second depth Z2 are various defects such as point defects and dislocations. Among the point defects, vacancies and compound vacancies, in particular, are formed. In this case, the concentration of crystal defects has a peak at a position slightly closer to the ion implantation surface (the lower surface 23 of the semiconductor substrate 10) from the second depth Z2.
　図２１は、水素の拡散係数Ｄと、第１のドーズ量Ｑとの関係を示す図である。図２１では、図２０に示した第１の例１６１と、第２の例１６２と、第３の例１６３のそれぞれをプロットしている。第１のドーズ量Ｑが増加すると、拡散係数Ｄは増加している。第１の深さＺ１に注入された水素は、通過領域１０６のダングリングボンドを終端しながら、第２の深さＺ２に向けて拡散する。第１のドーズ量Ｑが増加すると、ダングリングボンドが終端された領域を拡散する水素の割合が増えるので、水素が拡散しやすくなっていると考えられる。なお、実験条件等により拡散係数Ｄの値は変動する。図２１に示した拡散係数Ｄに対して、少なくとも±５０％以内の誤差は許容できる。±１００％以内の誤差も許容可能である。 FIG. 21 is a diagram showing the relationship between the hydrogen diffusion coefficient D and the first dose amount Q. In FIG. 21, the first example 161, the second example 162, and the third example 163 shown in FIG. 20 are plotted. As the first dose amount Q increases, the diffusion coefficient D increases. The hydrogen injected into the first depth Z1 diffuses toward the second depth Z2 while terminating the dangling bond in the passage region 106. When the first dose amount Q increases, the proportion of hydrogen diffusing in the region where the dangling bonds are terminated increases, and it is considered that hydrogen easily diffuses. The value of the diffusion coefficient D varies depending on experimental conditions and the like. An error of at least ±50% is acceptable with respect to the diffusion coefficient D shown in FIG. Errors within ±100% are also acceptable.
　図２２は、拡散係数Ｄと、アニール温度Ｔとの関係を示す図である。図２２は、図２０および図２１において説明した拡散係数を、複数のアニール温度Ｔについて取得して、アレニウスプロットしたグラフである。本例では、第１のドーズ量を、Ｑ＝１×１０１５／ｃｍ２とした。 FIG. 22 is a diagram showing the relationship between the diffusion coefficient D and the annealing temperature T. FIG. 22 is a graph obtained by acquiring the diffusion coefficient described in FIGS. 20 and 21 for a plurality of annealing temperatures T and performing Arrhenius plotting. In this example, the first dose amount was set to Q=1×10 15 /cm 2 .
　拡散係数Ｄは、Ｄ＝Ｄ０ｅｘｐ（－Ｅａ／ｋＢＴ）であらわされる。Ｄ０は定数、Ｅａは活性化エネルギー、ｋＢはボルツマン定数である。図２２のグラフから、Ｄ０＝０．１９０９５（ｃｍ２／ｓ）、Ｅａ＝１．２０４（ｅＶ）である。これにより、半導体基板１０における水素の拡散係数を算出できる。 The diffusion coefficient D is represented by D=D 0 exp(−Ea/k B T). D 0 is a constant, Ea is an activation energy, and k B is a Boltzmann constant. From the graph of FIG. 22, D 0 =0.19095 (cm 2 /s) and Ea=1.204 (eV). Thereby, the diffusion coefficient of hydrogen in the semiconductor substrate 10 can be calculated.
　図２３は、水素の拡散深さと、第１のドーズ量との関係を示す図である。図２３においては、図２０に示した第１の例１６１、第２の例１６２、第３の例１６３を黒丸でプロットしている。 FIG. 23 is a diagram showing the relationship between the hydrogen diffusion depth and the first dose amount. In FIG. 23, the first example 161, the second example 162, and the third example 163 shown in FIG. 20 are plotted with black circles.
　図２３に示すように、各プロットを直線で結ぶことで、それぞれの拡散深さｘに対する第１のドーズ量を決定できる。つまり、当該直線が、それぞれの拡散深さｘに対する、最小の第１のドーズ量を示している。第１注入段階Ｓ１９００において、当該直線より大きい第１のドーズ量を設定することで、通過領域１０６の全体のドナー濃度をベースドーピング濃度より大きくできる。一例として、第１のドーズ量Ｑ（ｉｏｎｓ／ｃｍ２）は、第２の深さＺ２を拡散深さｘ（μm）とした場合に、下式を満たしてよい。
　Ｑ≧１．６４９１×１０１３×ｅ０．０６１６１９ｘ As shown in FIG. 23, by connecting each plot with a straight line, the first dose amount with respect to each diffusion depth x can be determined. That is, the straight line indicates the minimum first dose amount for each diffusion depth x. In the first implantation step S1900, by setting the first dose amount larger than the straight line, the donor concentration of the entire passing region 106 can be made higher than the base doping concentration. As an example, the first dose amount Q (ions/cm 2 ) may satisfy the following equation when the second depth Z2 is the diffusion depth x (μm).
Q≧1.6491×10 13 ×e 0.061619x
　上述したように、第２の深さＺ２にヘリウムイオンを注入したときの結晶欠陥濃度のピークは、第２の深さＺ２よりも若干浅い位置に設けられる。図２３の横軸は、結晶欠陥濃度のピーク位置に対応している。このため、図２３の横軸に対応する長さＸ０の通過領域１０６を形成する場合には、イオン注入におけるストラグリングΔＲｐを考慮して、下式の飛程Ｒｐで、第２の深さＺ２にヘリウムイオンを注入する。
　Ｒｐ≧Ｘ０＋ΔＲｐ
　半導体基板１０の上面２１に設けられたトレンチ部の底部よりも、上面２１に近い位置に、結晶欠陥の濃度ピーク位置（下面２３から長さＸ０の位置）を設定することで、半導体基板１０の深さ方向のほぼ全体に、通過領域１０６を形成できる。 As described above, the peak of the crystal defect concentration when helium ions are implanted to the second depth Z2 is provided at a position slightly shallower than the second depth Z2. The horizontal axis of FIG. 23 corresponds to the peak position of the crystal defect concentration. Therefore, when forming the passage region 106 having the length X0 corresponding to the horizontal axis of FIG. 23, the straggling ΔRp in the ion implantation is taken into consideration, and the range Rp of the following formula is used to obtain the second depth Z2. Implant helium ions into.
Rp≧X0+ΔRp
By setting the concentration peak position of the crystal defect (the position of the length X0 from the lower surface 23) at a position closer to the upper surface 21 than the bottom of the trench portion provided on the upper surface 21 of the semiconductor substrate 10, The passage region 106 can be formed in almost the entire depth direction.
　なお、式（１）を変形した下の式（２）に基づいて、最小ドーズ量を算出してもよい。
Figure JPOXMLDOC01-appb-M000002
 　拡散係数Ｄは、図２２において説明した方法で算出する。図２３には、式（２）から算出した最小ドーズ量を、白丸でプロットしている。なお、拡散係数Ｄは、距離の２乗の次元を有しているので、拡散係数Ｄを水素の拡散深さｘの関数であらわしてもよい。 The minimum dose amount may be calculated based on the following equation (2) obtained by modifying the equation (1).
Figure JPOXMLDOC01-appb-M000002
 The diffusion coefficient D is calculated by the method described in FIG. In FIG. 23, the minimum dose amount calculated from the equation (2) is plotted by a white circle. Since the diffusion coefficient D has a dimension of the square of the distance, the diffusion coefficient D may be expressed as a function of the hydrogen diffusion depth x.
　図２４は、拡散係数Ｄと拡散深さｘの関係を示す図である。図２４においては、図２０における第１の例１６１、第２の例１６２、第３の例１６３をプロットしている。図２４に示すように、拡散深さｘが増加すると、拡散係数Ｄも増加する。 FIG. 24 is a diagram showing the relationship between the diffusion coefficient D and the diffusion depth x. In FIG. 24, the first example 161, the second example 162, and the third example 163 in FIG. 20 are plotted. As shown in FIG. 24, as the diffusion depth x increases, the diffusion coefficient D also increases.
　拡散深さｘが増加すると、第１の深さＺ１から、結晶欠陥の濃度ピークまでの距離が増加する。このため、通過領域１０６のうち、結晶欠陥が比較的に少ない領域の割合が増大する。結晶欠陥が少ないと拡散係数は大きくなるので、拡散深さｘが増加すると、通過領域１０６の平均的な拡散係数も大きくなる。 When the diffusion depth x increases, the distance from the first depth Z1 to the concentration peak of crystal defects increases. For this reason, the proportion of the region having relatively few crystal defects in the passage region 106 increases. Since the diffusion coefficient increases when the number of crystal defects is small, the average diffusion coefficient of the passage region 106 also increases when the diffusion depth x increases.
　なお、図２０から図２４においては、第２のドーズ量を１×１０１３／ｃｍ２としている。ただし、第２のドーズ量を変更しても、同様の方法で第１のドーズ量の最小ドーズ量を決定できる。また、第２のドーズ量を調整することで、通過領域１０６のドナー濃度を調整してもよい。第２のドーズ量を調整することで、通過領域１０６に形成される結晶欠陥の濃度を調整できる。また、アニール温度は３７０℃としていたが、アニール温度を変更しても、式（２）から最小ドーズ量を決定できる。 20 to 24, the second dose amount is set to 1×10 13 /cm 2 . However, even if the second dose amount is changed, the minimum dose amount of the first dose amount can be determined by the same method. Further, the donor concentration in the passage region 106 may be adjusted by adjusting the second dose amount. By adjusting the second dose amount, the concentration of crystal defects formed in the passage region 106 can be adjusted. Although the annealing temperature is set to 370° C., the minimum dose amount can be determined from the equation (2) even if the annealing temperature is changed.
　図２５は、アニール温度毎の、最小ドーズ量を規定する直線を示す図である。本例では、拡散深さによらず、拡散係数Ｄは一定とした。第１の注入工程Ｓ１９００においては、図２５の直線で示される最小ドーズ量より大きいドーズ量で、第１の深さＺ１に水素イオンを注入すればよい。 FIG. 25 is a diagram showing straight lines defining the minimum dose amount for each annealing temperature. In this example, the diffusion coefficient D is constant regardless of the diffusion depth. In the first implantation step S1900, hydrogen ions may be implanted at the first depth Z1 with a dose amount larger than the minimum dose amount shown by the straight line in FIG.
　図２６は、第２のドーズ量と、第１のドーズ量の最小ドーズ量との関係を示す図である。本例では、拡散深さｘ毎に、当該関係を示している。第１の注入工程Ｓ１９００においては、図２６の直線で示される最小ドーズ量より大きいドーズ量で、第１の深さＺ１に水素イオンを注入すればよい。 FIG. 26 is a diagram showing the relationship between the second dose amount and the minimum dose amount of the first dose amount. In this example, the relationship is shown for each diffusion depth x. In the first implantation step S1900, hydrogen ions may be implanted to the first depth Z1 with a dose amount larger than the minimum dose amount shown by the straight line in FIG.
　図２７は、第１の深さＺ１の一例を説明する図である。図２７においては、半導体基板１０の深さ方向におけるドナー濃度分布、水素化学濃度分布およびヘリウム化学濃度分布を示している。水素化学濃度分布およびヘリウム化学濃度分布は、ピークの近傍だけを模式的に示している。図２７においては、半導体基板１０の上面２１の近傍（下面２３からの距離が１００μｍ以上の領域）における分布を省略している。また、半導体基板１０のＮ型の領域におけるキャリア濃度分布を、ドナー濃度分布として用いてよい。 FIG. 27 is a diagram illustrating an example of the first depth Z1. 27, the donor concentration distribution, the hydrogen chemical concentration distribution, and the helium chemical concentration distribution in the depth direction of the semiconductor substrate 10 are shown. The hydrogen chemical concentration distribution and the helium chemical concentration distribution schematically show only the vicinity of the peak. In FIG. 27, the distribution in the vicinity of the upper surface 21 of the semiconductor substrate 10 (a region where the distance from the lower surface 23 is 100 μm or more) is omitted. Further, the carrier concentration distribution in the N-type region of the semiconductor substrate 10 may be used as the donor concentration distribution.
　本例においては、水素濃度ピーク１３１の第１の深さＺ１が、半導体基板１０の下面２３から、深さ方向に５μｍ以下の範囲に含まれている。半導体装置１００において、第１の深さＺ１以外の構成は、図１から図２６において説明したいずれかの態様と同一である。本例の半導体装置１００のドナー濃度分布は、図１０の例と同様である。 In this example, the first depth Z1 of the hydrogen concentration peak 131 is included in the range of 5 μm or less in the depth direction from the lower surface 23 of the semiconductor substrate 10. In the semiconductor device 100, the configuration other than the first depth Z1 is the same as any one of the modes described in FIGS. 1 to 26. The donor concentration distribution of the semiconductor device 100 of this example is similar to that of the example of FIG.
　第１の深さＺ１を、下面２３の近傍に配置することで、第１の深さＺ１と、第２の深さＺ２との距離を広くできる。このため、半導体基板１０のより広い範囲において、ドナー濃度を精度よく調整できる。第１の深さＺ１は、下面２３から４μｍ以内の範囲に含まれてよく、３μｍ以内の範囲に含まれてもよい。 By arranging the first depth Z1 near the lower surface 23, the distance between the first depth Z1 and the second depth Z2 can be widened. Therefore, the donor concentration can be accurately adjusted in a wider range of the semiconductor substrate 10. The first depth Z1 may be included in the range of 4 μm or less from the lower surface 23, and may be included in the range of 3 μm or less.
　より広い範囲に水素を拡散させるために、第１の深さＺ１に注入する水素のドーズ量をより高くすることが好ましい。本例において水素の第１の深さＺ１に注入する水素のドーズ量は、１×１０１５ａｔｏｍｓ／ｃｍ２以上であってよく、１×１０１６ａｔｏｍｓ／ｃｍ２以上であってよく、１×１０１７ａｔｏｍｓ／ｃｍ２以上であってよく、１×１０１８ａｔｏｍｓ／ｃｍ２以上であってもよい。第１の深さＺ１には、水素ドナーによる第１のドナー濃度ピーク１１１が形成されてよい。第１のドナー濃度ピーク１１１のドナー濃度は、１×１０１５／ｃｍ３以上であってよく、１×１０１６／ｃｍ３以上であってもよい。第１のドナー濃度ピーク１１１のドナー濃度は、１×１０１７／ｃｍ３以下であってよい。 In order to diffuse hydrogen in a wider range, it is preferable to increase the dose amount of hydrogen injected into the first depth Z1. In this example, the dose amount of hydrogen injected into the first depth Z1 of hydrogen may be 1×10 15 atoms/cm 2 or more, 1×10 16 atoms/cm 2 or more, and 1×. It may be 10 17 atoms/cm 2 or more, or 1×10 18 atoms/cm 2 or more. A first donor concentration peak 111 due to a hydrogen donor may be formed at the first depth Z1. The donor concentration of the first donor concentration peak 111 may be 1×10 15 /cm 3 or higher, or 1×10 16 /cm 3 or higher. The donor concentration of the first donor concentration peak 111 may be 1×10 17 /cm 3 or less.
　第１の深さＺ１への水素の注入は、プラズマドーピングにより行ってよい。プラズマドーピングにおいては、半導体基板１０を収容した収容容器内に、プラズマ励起用のガスと、水素を含む原料ガスを供給する。励起用ガスは、アルゴン等の不活性元素を含んでよい。原料ガスは、フォスフィン（ＰＨ３）等を用いてよい。収容容器内においてこれらのガスを用いてプラズマを発生させ、半導体基板１０の下面２３をプラズマ中に暴露することで、下面２３からみて浅い位置に、高濃度の水素を容易に注入できる。また、プラズマドーピングを用いて、下面２３近傍の浅い位置に水素を注入することで、半導体基板１０における結晶欠陥の発生を抑制できる。また、結晶欠陥が少ないのでアニール温度を低くでき、半導体装置１００の製造におけるスループットを向上できる。ただし、第１の深さＺ１への水素注入の方法は、プラズマドーピングに限定されない。 The implantation of hydrogen to the first depth Z1 may be performed by plasma doping. In plasma doping, a gas for plasma excitation and a raw material gas containing hydrogen are supplied into a container for housing the semiconductor substrate 10. The excitation gas may include an inert element such as argon. As the source gas, phosphine (PH3) or the like may be used. By generating plasma using these gases in the container and exposing the lower surface 23 of the semiconductor substrate 10 to the plasma, high-concentration hydrogen can be easily injected at a position shallower than the lower surface 23. Further, by using plasma doping to inject hydrogen into a shallow position near the lower surface 23, it is possible to suppress the generation of crystal defects in the semiconductor substrate 10. Further, since there are few crystal defects, the annealing temperature can be lowered, and the throughput in manufacturing the semiconductor device 100 can be improved. However, the method of hydrogen implantation to the first depth Z1 is not limited to plasma doping.
　ヘリウム濃度ピーク１４１の第２の深さＺ２へのヘリウムの注入は、プラズマドーピング以外の方法で行ってよい。ヘリウムイオンを電界等で加速させて、第２の深さＺ２にヘリウムを注入してよい。第２の深さ位置Ｚ２は、下面２３から深さ方向に８０μｍ以上離れていてもよい。第２の深さ位置Ｚ２は、下面２３から９０μｍ以上離れていてよく、１００μｍ以上離れていてもよい。第１の深さ位置と第２の深さ位置の深さ方向における距離は、半導体基板１０の深さ方向の厚みの５０％以上であってよく、６５％以上であってよく、８０％以上であってもよい。 The helium may be injected to the second depth Z2 of the helium concentration peak 141 by a method other than plasma doping. Helium ions may be accelerated to an electric field or the like to inject helium to the second depth Z2. The second depth position Z2 may be separated from the lower surface 23 by 80 μm or more in the depth direction. The second depth position Z2 may be separated from the lower surface 23 by 90 μm or more, and may be separated by 100 μm or more. The distance between the first depth position and the second depth position in the depth direction may be 50% or more, 65% or more, and 80% or more of the thickness of the semiconductor substrate 10 in the depth direction. May be
　図２８は、半導体基板１０の深さ方向におけるドナー濃度分布、水素化学濃度分布およびヘリウム化学濃度分布の他の例を示している。水素化学濃度分布およびヘリウム化学濃度分布は、ピークの近傍だけを模式的に示している。本例の第１の深さＺ１は、図２７の例と同一である。また、第２の深さＺ２は、半導体基板１０の上面２１側に配置されていてよい。上面２１側とは、半導体基板１０の深さ方向における中央から、上面２１までの領域を指す。 FIG. 28 shows another example of the donor concentration distribution, the hydrogen chemical concentration distribution, and the helium chemical concentration distribution in the depth direction of the semiconductor substrate 10. The hydrogen chemical concentration distribution and the helium chemical concentration distribution schematically show only the vicinity of the peak. The first depth Z1 of this example is the same as the example of FIG. The second depth Z2 may be arranged on the upper surface 21 side of the semiconductor substrate 10. The upper surface 21 side refers to a region from the center of the semiconductor substrate 10 in the depth direction to the upper surface 21.
　図２７および図２８のいずれの例においても、水素化学濃度分布は、第１の深さＺ１と、第２の深さＺ２との間に、１つ以上の水素濃度ピーク１９４を有してよい。水素濃度ピーク１９４は、図６等において説明したバッファ領域２０に配置されてよい。水素濃度ピーク１３１は、バッファ領域２０に配置されてよく、バッファ領域２０と、下面２３との間に配置されてもよい。 27 and 28, the hydrogen chemical concentration distribution may have one or more hydrogen concentration peaks 194 between the first depth Z1 and the second depth Z2. .. The hydrogen concentration peak 194 may be arranged in the buffer region 20 described with reference to FIG. The hydrogen concentration peak 131 may be arranged in the buffer region 20, or may be arranged between the buffer region 20 and the lower surface 23.
　図２９は、水素濃度ピーク１３１の近傍における、水素化学濃度分布と、アルゴン化学濃度分布の一例を示す図である。本例においては、水素濃度ピーク１３１は、プラズマドーピングにより注入された水素に対応するピークであり、水素濃度ピーク１９４は、プラズマドーピング以外の方法で注入された水素に対応するピークである。 FIG. 29 is a diagram showing an example of the hydrogen chemical concentration distribution and the argon chemical concentration distribution in the vicinity of the hydrogen concentration peak 131. In this example, the hydrogen concentration peak 131 is a peak corresponding to hydrogen injected by plasma doping, and the hydrogen concentration peak 194 is a peak corresponding to hydrogen injected by a method other than plasma doping.
　プラズマドーピングにより第１の深さ位置Ｚ１に水素を注入すると、第１の深さ位置Ｚ１の近傍に、水素以外の不純物が注入される場合がある。例えば、プラズマ励起用にアルゴンガスを用いている場合、第１の深さ位置Ｚ１の近傍にアルゴンが注入される場合がある。図２９においては、深さ位置Ｚ０にアルゴン濃度ピーク１９６を示している。 When hydrogen is injected into the first depth position Z1 by plasma doping, impurities other than hydrogen may be injected in the vicinity of the first depth position Z1. For example, when argon gas is used for plasma excitation, argon may be injected in the vicinity of the first depth position Z1. In FIG. 29, an argon concentration peak 196 is shown at the depth position Z0.
　深さ位置Ｚ０は、下面２３と、第１の深さ位置Ｚ１との間に配置されてよい。アルゴンは水素よりも重い元素なので、アルゴン濃度ピーク１９６は、水素濃度ピーク１３１よりも浅い位置に形成されやすい。 The depth position Z0 may be arranged between the lower surface 23 and the first depth position Z1. Since argon is an element heavier than hydrogen, the argon concentration peak 196 is likely to be formed at a position shallower than the hydrogen concentration peak 131.
　本例では、第１の深さ位置Ｚ１と、第２の深さ位置Ｚ２との間には、アルゴン化学濃度のピークが設けられていない。第１の深さ位置Ｚ１と、第２の深さ位置Ｚ２との間における水素濃度ピーク１９４は、プラズマドーピング以外の方法で形成されているので、水素濃度ピーク１９４の近傍には、アルゴンが注入されていない。第１の深さ位置Ｚ１と、第２の深さ位置Ｚ２との間におけるアルゴン化学濃度は、アルゴン濃度ピーク１９６よりも小さい。第１の深さ位置Ｚ１と、第２の深さ位置Ｚ２との間におけるアルゴン化学濃度の最大値は、下面２３と第１の深さ位置Ｚ１との間におけるアルゴン化学濃度の最小値以下であってよい。 In this example, no peak of the chemical concentration of argon is provided between the first depth position Z1 and the second depth position Z2. Since the hydrogen concentration peak 194 between the first depth position Z1 and the second depth position Z2 is formed by a method other than plasma doping, argon is injected in the vicinity of the hydrogen concentration peak 194. It has not been. The argon chemical concentration between the first depth position Z1 and the second depth position Z2 is smaller than the argon concentration peak 196. The maximum value of the argon chemical concentration between the first depth position Z1 and the second depth position Z2 is less than or equal to the minimum value of the argon chemical concentration between the lower surface 23 and the first depth position Z1. You can
　なお、プラズマドーピングに用いるガスの組成に応じて、半導体基板１０には、アルゴンに代えて、他の不純物が注入されていてもよい。プラズマドーピングにＰＨ３ガスを用いた場合、下面２３と第１の深さ位置Ｚ１との間には、リン濃度ピークが設けられてよい。プラズマドーピングにＢＦ３ガスを用いた場合、下面２３と第１の深さ位置Ｚ１との間には、フッ素濃度ピークが設けられてよく、ボロン濃度ピークが設けられてもよい。アルゴン、リン、フッ素、または、ボロンの濃度ピークの濃度値は、水素濃度ピーク１３１の濃度値よりも小さくてよい。アルゴン、リン、フッ素、または、ボロンの濃度ピークの濃度値は、水素濃度ピーク１３１の濃度値の半分以下であってよく、１／１０以下であってもよい。 Note that other impurities may be implanted into the semiconductor substrate 10 instead of argon, depending on the composition of the gas used for plasma doping. When PH3 gas is used for plasma doping, a phosphorus concentration peak may be provided between the lower surface 23 and the first depth position Z1. When BF3 gas is used for plasma doping, a fluorine concentration peak may be provided between the lower surface 23 and the first depth position Z1, and a boron concentration peak may be provided. The concentration value of the concentration peak of argon, phosphorus, fluorine, or boron may be smaller than the concentration value of the hydrogen concentration peak 131. The concentration value of the concentration peak of argon, phosphorus, fluorine, or boron may be half or less of the concentration value of the hydrogen concentration peak 131, or 1/10 or less.
　図３０は、半導体装置１００の他の構造例を示す図である。本例の半導体装置１００は、図１１に示した例と同様に、トランジスタ部７０およびダイオード部８０を備える。トランジスタ部７０の構造は、図６に示した例と同一である。トランジスタ部７０およびダイオード部８０は、Ｘ軸方向に隣り合って設けられている。 FIG. 30 is a diagram showing another structural example of the semiconductor device 100. The semiconductor device 100 of this example includes a transistor section 70 and a diode section 80, as in the example shown in FIG. The structure of the transistor unit 70 is the same as the example shown in FIG. The transistor section 70 and the diode section 80 are provided adjacent to each other in the X-axis direction.
　本例のダイオード部８０は、トランジスタ部７０の構成に対して、ゲートトレンチ部４０に代えてダミートレンチ部３０を有し、コレクタ領域２２に代えてカソード領域８２を有し、且つ、エミッタ領域１２を有さない点で相違する。他の構造は、トランジスタ部７０と同様である。 The diode part 80 of this example has a dummy trench part 30 in place of the gate trench part 40, a cathode region 82 in place of the collector region 22, and a emitter region 12 in addition to the structure of the transistor part 70. The difference is that it does not have. The other structure is similar to that of the transistor section 70.
　ダミートレンチ部３０は、ゲートトレンチ部４０と同一の構造を有してよい。ダミートレンチ部３０は、ダミー絶縁膜３２およびダミー導電部３４を有する。ダミー絶縁膜３２およびダミー導電部３４は、ゲート絶縁膜４２およびゲート導電部４４と同一の構造および材料を有してよい。ただし、ゲート導電部４４はゲート電極に電気的に接続されるのに対して、ダミー導電部３４はエミッタ電極５２に電気的に接続されている。なお、ダミートレンチ部３０は、トランジスタ部７０にも設けられてよい。つまり、トランジスタ部７０における一部のゲートトレンチ部４０が、ダミートレンチ部３０に置き換えられていてよい。 The dummy trench section 30 may have the same structure as the gate trench section 40. The dummy trench portion 30 has a dummy insulating film 32 and a dummy conductive portion 34. The dummy insulating film 32 and the dummy conductive portion 34 may have the same structure and material as the gate insulating film 42 and the gate conductive portion 44. However, the gate conductive portion 44 is electrically connected to the gate electrode, while the dummy conductive portion 34 is electrically connected to the emitter electrode 52. The dummy trench section 30 may also be provided in the transistor section 70. That is, part of the gate trench section 40 in the transistor section 70 may be replaced with the dummy trench section 30.
　カソード領域８２は、コレクタ領域２２と同様に、半導体基板１０の下面２３に露出している。カソード領域８２は、下面２３において、コレクタ電極５４と接続されている。カソード領域８２は、リン等のＮ型不純物がドープされたＮ＋型の領域である。カソード領域８２とドリフト領域１８との間には、バッファ領域２０が設けられてよい。 Like the collector region 22, the cathode region 82 is exposed on the lower surface 23 of the semiconductor substrate 10. The cathode region 82 is connected to the collector electrode 54 on the lower surface 23. The cathode region 82 is an N+ type region doped with an N type impurity such as phosphorus. The buffer region 20 may be provided between the cathode region 82 and the drift region 18.
　また、ダイオード部８０においては、ベース領域１４が上面２１に露出していてよい。ダイオード部８０のベース領域１４は、エミッタ電極５２に電気的に接続されている。このような構成により、ダイオード部８０がダイオードとして機能する。 Further, in the diode portion 80, the base region 14 may be exposed on the upper surface 21. The base region 14 of the diode portion 80 is electrically connected to the emitter electrode 52. With such a configuration, the diode section 80 functions as a diode.
　本例においては、ダイオード部８０においても、第１の深さ位置Ｚ１に水素、第２の深さ位置Ｚ２にヘリウムが注入されている。また、ダイオード部８０においても、トランジスタ部７０と同様の通過領域が形成されている。トランジスタ部７０における各濃度分布は、図１から図２９において説明したいずれかの態様と同一であってよい。ダイオード部８０の深さ方向における水素化学濃度分布は、トランジスタ部７０の深さ方向における水素化学濃度分布と同一であってよい。ダイオード部８０の深さ方向におけるヘリウム化学濃度分布は、トランジスタ部７０の深さ方向におけるヘリウム化学濃度分布と同一であってよい。 In this example, also in the diode portion 80, hydrogen is injected at the first depth position Z1 and helium is injected at the second depth position Z2. Further, also in the diode portion 80, a passage region similar to that of the transistor portion 70 is formed. Each concentration distribution in the transistor section 70 may be the same as any one of the modes described in FIGS. 1 to 29. The hydrogen chemical concentration distribution in the depth direction of the diode part 80 may be the same as the hydrogen chemical concentration distribution in the depth direction of the transistor part 70. The helium chemical concentration distribution in the depth direction of the diode portion 80 may be the same as the helium chemical concentration distribution in the depth direction of the transistor portion 70.
　図３１は、図３０のＤ－Ｄ線における、キャリア濃度分布、水素化学濃度分布およびボロン化学濃度分布の一例を示している。Ｄ－Ｄ線は、トランジスタ部７０において、コレクタ領域２２と、バッファ領域２０の一部とを通過する。本例のコレクタ領域２２は、ボロンを注入して形成されている。本例のコレクタ領域２２のボロンは、水素濃度ピーク１３１の水素とは別の工程で注入されている。コレクタ領域２２のボロンの少なくとも一部は、水素濃度ピーク１３１の水素を注入するためのプラズマドーピングにおいて注入されてもよい。 FIG. 31 shows an example of the carrier concentration distribution, the hydrogen chemical concentration distribution, and the boron chemical concentration distribution on the DD line of FIG. The DD line passes through the collector region 22 and a part of the buffer region 20 in the transistor unit 70. The collector region 22 of this example is formed by implanting boron. Boron in the collector region 22 of this example is implanted in a process different from that for hydrogen in the hydrogen concentration peak 131. At least a part of boron in the collector region 22 may be implanted in plasma doping for implanting hydrogen in the hydrogen concentration peak 131.
　図７等の例においては、水素濃度ピーク１３１は、バッファ領域２０に配置されていた。本例における水素濃度ピーク１３１は、カソード領域８２およびコレクタ領域２２に配置されている。カソード領域８２およびコレクタ領域２２のドーピング濃度は非常に高いので、水素濃度ピーク１３１をカソード領域８２およびコレクタ領域２２に設けることで、水素濃度ピーク１３１によって高濃度の水素ドナーが発生した場合でも、キャリア濃度分布の形状の変動を抑制できる。このため、半導体装置１００の特性への影響を抑制しやすくなる。 In the example of FIG. 7 etc., the hydrogen concentration peak 131 was arranged in the buffer region 20. The hydrogen concentration peak 131 in this example is arranged in the cathode region 82 and the collector region 22. Since the doping concentration of the cathode region 82 and the collector region 22 is very high, by providing the hydrogen concentration peak 131 in the cathode region 82 and the collector region 22, even if a high concentration hydrogen donor is generated by the hydrogen concentration peak 131, carrier It is possible to suppress variations in the shape of the concentration distribution. Therefore, it is easy to suppress the influence on the characteristics of the semiconductor device 100.
　水素濃度ピーク１３１の濃度は、第１の深さ位置Ｚ１において、水素ドナー濃度が、キャリア濃度よりも十分小さくなるように設定される。水素の活性化率は１％程度である。第１の深さ位置Ｚ１において、水素化学濃度の１％が、ボロン化学濃度より小さくてよい。 The concentration of the hydrogen concentration peak 131 is set so that the hydrogen donor concentration is sufficiently smaller than the carrier concentration at the first depth position Z1. The activation rate of hydrogen is about 1%. At the first depth position Z1, 1% of the hydrogen chemical concentration may be lower than the boron chemical concentration.
　また、コレクタ領域２２におけるキャリア濃度分布のピーク位置は、水素濃度ピーク１３１よりも、ボロン化学濃度のピークの近くに配置される。図３１の例において、ボロン化学濃度のピークは、下面２３に配置されている。コレクタ領域２２におけるキャリア濃度分布のピーク位置は、ボロン化学濃度のピーク位置と同一であってもよい。水素濃度ピーク１３１は、コレクタ領域２２におけるキャリア濃度分布のピークと、バッファ領域２０との間に配置されてよい。本例において、コレクタ領域２２におけるキャリア濃度分布のピーク位置は、下面２３と一致している。なお、バッファ領域２０においては、水素濃度ピーク１９４の深さ位置と、キャリア濃度分布のピーク２４の深さ位置とが一致していてよい。 The peak position of the carrier concentration distribution in the collector region 22 is located closer to the boron chemical concentration peak than the hydrogen concentration peak 131. In the example of FIG. 31, the peak of the boron chemical concentration is located on the lower surface 23. The peak position of the carrier concentration distribution in the collector region 22 may be the same as the peak position of the chemical concentration of boron. The hydrogen concentration peak 131 may be arranged between the peak of the carrier concentration distribution in the collector region 22 and the buffer region 20. In this example, the peak position of the carrier concentration distribution in the collector region 22 coincides with the lower surface 23. In the buffer region 20, the depth position of the hydrogen concentration peak 194 may coincide with the depth position of the peak 24 of the carrier concentration distribution.
　図３２は、図３０のＥ－Ｅ線における、キャリア濃度分布、水素化学濃度分布およびリン化学濃度分布の一例を示している。Ｅ－Ｅ線は、ダイオード部８０において、カソード領域８２と、バッファ領域２０の一部とを通過する。本例のカソード領域８２は、リンを注入して形成されている。カソード領域８２のリンは、水素濃度ピーク１３１の水素とは別の工程で注入されている。カソード領域８２のリンの少なくとも一部は、水素濃度ピーク１３１の水素を注入するためのプラズマドーピングにおいて注入されてもよい。 FIG. 32 shows an example of the carrier concentration distribution, the hydrogen chemical concentration distribution, and the phosphorus chemical concentration distribution on the line EE of FIG. The EE line passes through the cathode region 82 and a part of the buffer region 20 in the diode section 80. The cathode region 82 of this example is formed by implanting phosphorus. Phosphorus in the cathode region 82 is implanted in a process different from that for hydrogen in the hydrogen concentration peak 131. At least a portion of phosphorus in the cathode region 82 may be implanted in plasma doping for implanting hydrogen in the hydrogen concentration peak 131.
　本例における水素濃度ピーク１３１は、カソード領域８２およびコレクタ領域２２に配置されている。水素濃度ピーク１３１の濃度は、第１の深さＺ１において、水素ドナー濃度が、キャリア濃度よりも十分小さくなるように設定される。水素の活性化率は１％程度である。第１の深さＺ１において、水素化学濃度の１％が、リン化学濃度より小さくてよい。 The hydrogen concentration peak 131 in this example is arranged in the cathode region 82 and the collector region 22. The concentration of the hydrogen concentration peak 131 is set so that the hydrogen donor concentration is sufficiently smaller than the carrier concentration at the first depth Z1. The activation rate of hydrogen is about 1%. At the first depth Z1, 1% of the hydrogen chemical concentration may be less than the phosphorus chemical concentration.
　また、カソード領域８２におけるキャリア濃度分布のピーク位置は、水素濃度ピーク１３１よりも、リン化学濃度のピークの近くに配置される。図３２の例において、リン化学濃度のピークは、下面２３に配置されている。カソード領域８２におけるキャリア濃度分布のピーク位置は、リン化学濃度のピーク位置と同一であってもよい。水素濃度ピーク１３１は、カソード領域８２におけるキャリア濃度分布のピークと、バッファ領域２０との間に配置されてよい。本例において、カソード領域８２におけるキャリア濃度分布のピーク位置は、下面２３と一致している。なお、バッファ領域２０においては、水素濃度ピーク１９４の深さ位置と、キャリア濃度分布のピーク２４の深さ位置とが一致していてよい。 The peak position of the carrier concentration distribution in the cathode region 82 is located closer to the phosphorus chemical concentration peak than the hydrogen concentration peak 131. In the example of FIG. 32, the phosphorus chemical concentration peak is located on the lower surface 23. The peak position of the carrier concentration distribution in the cathode region 82 may be the same as the peak position of the phosphorus chemical concentration. The hydrogen concentration peak 131 may be arranged between the peak of the carrier concentration distribution in the cathode region 82 and the buffer region 20. In this example, the peak position of the carrier concentration distribution in the cathode region 82 coincides with the lower surface 23. In the buffer region 20, the depth position of the hydrogen concentration peak 194 may coincide with the depth position of the peak 24 of the carrier concentration distribution.
　図３３は、半導体装置１００の製造方法の一部の工程を示す図である。図３３に示す工程の前に、各トレンチ部、エミッタ領域１２、ベース領域１４、蓄積領域１６等の上面２１側の構造を形成してよい。 FIG. 33 is a diagram showing a part of the method of manufacturing the semiconductor device 100. Before the step shown in FIG. 33, the structure of each trench portion, the emitter region 12, the base region 14, the storage region 16 and the like on the upper surface 21 side may be formed.
　本例では、注入段階Ｓ３３００において、半導体基板１０の下面２３から第２の深さＺ２にヘリウムイオンを注入する。注入段階Ｓ３３００は、図１９の例における第２注入段階Ｓ１９０２と同一であってよい。 In this example, in the implantation step S3300, helium ions are implanted from the lower surface 23 of the semiconductor substrate 10 to the second depth Z2. The injection step S3300 may be the same as the second injection step S1902 in the example of FIG.
　また、注入段階Ｓ３３０２において、半導体基板１０の下面２３から第１の深さＺ１に水素イオンを注入する。注入段階Ｓ３３０２においては、プラズマドーピングにより、水素イオンを注入する。注入段階Ｓ３３０２における水素のドーズ量は、図１９の例の第１注入段階Ｓ１９００における水素のドーズ量と同一であってよい。注入段階Ｓ３３００および注入段階Ｓ３３０２は、いずれを先に行ってもよい。 Also, in the implantation step S3302, hydrogen ions are implanted from the lower surface 23 of the semiconductor substrate 10 to the first depth Z1. In the implantation step S3302, hydrogen ions are implanted by plasma doping. The dose of hydrogen in the implantation step S3302 may be the same as the dose of hydrogen in the first implantation step S1900 of the example of FIG. Either the injection step S3300 or the injection step S3302 may be performed first.
　注入段階Ｓ３３００および注入段階Ｓ３３０２の後に、拡散段階Ｓ３３０４を行う。拡散段階Ｓ３３０４は、図１９の例における拡散段階Ｓ１９０４と同様である。拡散段階Ｓ３３０４において水素を拡散させることで、通過領域１０６における結晶欠陥と水素とが結合してドナー化する。これにより、通過領域１０６におけるドナー濃度を高めることができる。 A diffusion step S3304 is performed after the injection step S3300 and the injection step S3302. The spreading step S3304 is similar to the spreading step S1904 in the example of FIG. By diffusing hydrogen in the diffusion step S3304, the crystal defects in the passage region 106 and hydrogen are combined to form a donor. Thereby, the donor concentration in the passage region 106 can be increased.
　拡散段階Ｓ３３０４の後に、研削段階Ｓ３３０６を行う。研削段階Ｓ３３０６では、半導体基板１０の下面２３側を化学機械研磨（ＣＭＰ）等により研削する。研削段階Ｓ３３０６では、第１の深さＺ１よりも浅い範囲を研削してよく、第１の深さＺ１よりも深い範囲を研削してもよい。これにより、水素が高濃度に分布している領域を研削できるので、下面２３の近傍における水素量を低減できる。 A grinding step S3306 is performed after the diffusion step S3304. In the grinding step S3306, the lower surface 23 side of the semiconductor substrate 10 is ground by chemical mechanical polishing (CMP) or the like. In the grinding step S3306, a range shallower than the first depth Z1 may be ground, or a range deeper than the first depth Z1 may be ground. As a result, the region where hydrogen is distributed at a high concentration can be ground, and the amount of hydrogen near the lower surface 23 can be reduced.
　研削段階Ｓ３３０６の後に、下面側構造形成段階Ｓ３３０８において、コレクタ領域２２、カソード領域８２およびバッファ領域２０等の下面２３側の構造を形成する。下面側構造形成段階Ｓ３３０８においては、カソード領域８２およびバッファ領域２０にドーパントを注入した後に、下面２３の近傍をレーザーアニールしてよい。これにより、半導体基板１０の下面２３の近傍を局所的に高温で熱処理できる。また、レーザーアニール後に、バッファ領域２０に水素等のドーパントを注入してよい。バッファ領域２０にドーパントを注入した後、半導体基板１０の全体をアニール炉により熱処理してよい。 After the grinding step S3306, in the lower surface side structure forming step S3308, structures on the lower surface 23 side such as the collector region 22, the cathode region 82, and the buffer region 20 are formed. In the lower surface side structure forming step S3308, after the dopant is injected into the cathode region 82 and the buffer region 20, the vicinity of the lower surface 23 may be laser annealed. Thereby, the vicinity of the lower surface 23 of the semiconductor substrate 10 can be locally heat-treated at a high temperature. In addition, a dopant such as hydrogen may be injected into the buffer region 20 after laser annealing. After implanting the dopant in the buffer region 20, the entire semiconductor substrate 10 may be heat-treated in an annealing furnace.
　図３４は、半導体装置１００の製造方法の一部の工程を示す図である。本例の製造方法は、図３３の研削段階Ｓ３３０６に代えて、レーザーアニール段階Ｓ３３０７を備える点で相違する。他の工程は、図３３の例と同一である。 FIG. 34 is a diagram showing a part of the method of manufacturing the semiconductor device 100. The manufacturing method of this example is different in that a laser annealing step S3307 is provided instead of the grinding step S3306 of FIG. The other steps are the same as in the example of FIG.
　レーザーアニール段階Ｓ３３０７では、半導体基板１０の下面２３をレーザーアニールする。レーザーアニール段階Ｓ３３０７においては、第１の深さＺ１の近傍にレーザーを照射してよい。これにより、第１の深さＺ１の近傍における水素の少なくとも一部を、半導体基板１０の外部に放出できる。これにより、第１の深さＺ１の近傍における水素化学濃度を低減できる。レーザーアニール段階Ｓ３３０７では、水素濃度ピーク１３１が残存するようにレーザーを照射してよく、水素濃度ピーク１３１が残存しないようにレーザーを照射してもよい。なお、レーザーが照射されても、アルゴン等の重い元素は、水素に比べて半導体基板１０に残存しやすい。このため、レーザーアニール段階Ｓ３３０７を行っても、半導体基板１０には、図２９に示したアルゴン等の不純物の濃度ピークが存在する場合がある。 In the laser annealing step S3307, the lower surface 23 of the semiconductor substrate 10 is laser-annealed. In the laser annealing step S3307, a laser may be irradiated near the first depth Z1. Thereby, at least a part of hydrogen in the vicinity of the first depth Z1 can be released to the outside of the semiconductor substrate 10. Thereby, the hydrogen chemical concentration in the vicinity of the first depth Z1 can be reduced. In the laser annealing step S3307, the laser may be irradiated so that the hydrogen concentration peak 131 remains, or the laser may be irradiated so that the hydrogen concentration peak 131 does not remain. Note that even when irradiated with laser, a heavy element such as argon is likely to remain in the semiconductor substrate 10 as compared with hydrogen. Therefore, even if the laser annealing step S3307 is performed, the semiconductor substrate 10 may have the impurity concentration peaks such as argon shown in FIG.
　また、レーザーアニール段階Ｓ３３０７においては、トランジスタ部７０にレーザーを照射し、ダイオード部８０にはレーザーを照射しなくてもよい。ダイオード部８０の下面２３に高濃度の水素ドナーが残存しても、特性に与える影響は比較的に小さい。この場合、ダイオード部８０の第１の深さＺ１における水素化学濃度は、トランジスタ部７０の第１の深さＺ１における水素化学濃度よりも高い。 Also, in the laser annealing step S3307, the transistor section 70 may be irradiated with the laser and the diode section 80 may not be irradiated with the laser. Even if a high-concentration hydrogen donor remains on the lower surface 23 of the diode portion 80, the influence on the characteristics is relatively small. In this case, the chemical hydrogen concentration at the first depth Z1 of the diode portion 80 is higher than the chemical hydrogen concentration at the first depth Z1 of the transistor portion 70.
　図１９、図３３、図３４に示した例において、第１の深さＺ１へ水素イオンの注入、第２の深さＺ２へのヘリウムイオンの注入および熱処理は、下面側構造を形成する前に行ってよく、下面側構造を形成した後に行ってよく、下面側構造を形成している間に行ってもよい。 In the examples shown in FIGS. 19, 33, and 34, the implantation of hydrogen ions to the first depth Z1, the implantation of helium ions to the second depth Z2, and the heat treatment are performed before forming the lower surface side structure. It may be performed after forming the lower surface side structure, or may be performed while forming the lower surface side structure.
　図３５は、下面側構造形成段階において、第１の深さＺ１に水素イオンを注入し、第２の深さＺ２にヘリウムイオンを注入する工程の一例を示す。本例においては、第１の深さＺ１への水素イオンの注入、第２の深さＺ２へのヘリウムイオンの注入および熱処理は、バッファ領域２０を形成するバッファ領域形成段階Ｓ３５０４で行う。 FIG. 35 shows an example of a step of implanting hydrogen ions to the first depth Z1 and implanting helium ions to the second depth Z2 in the lower surface side structure formation step. In this example, the implantation of hydrogen ions to the first depth Z1, the implantation of helium ions to the second depth Z2, and the heat treatment are performed in the buffer region formation step S3504 of forming the buffer region 20.
　下面側構造形成段階は、トレンチ部等の上面側構造形成段階Ｓ３５００よりも後に行ってよい。下面側構造形成段階は、コレクタ領域形成段階Ｓ３５０２と、バッファ領域形成段階Ｓ３５０４を有する。図３５では、下面側構造形成段階の他の段階を省略している。本例では、バッファ領域形成段階Ｓ３５０４において、第１の深さＺ１へ水素イオン、第２の深さＺ２へヘリウムイオンを注入する。Ｓ３５０４においては、水素イオンを注入した後に半導体基板１０を熱処理して水素イオンおよびヘリウムイオンを拡散させる。下面側構造形成段階の後に、コレクタ電極形成段階Ｓ３５０６を行ってよい。 The lower surface side structure forming step may be performed after the upper surface side structure forming step S3500 such as the trench portion. The lower surface side structure forming step includes a collector area forming step S3502 and a buffer area forming step S3504. In FIG. 35, the other steps of the lower surface side structure forming step are omitted. In this example, in the buffer region forming step S3504, hydrogen ions are implanted into the first depth Z1 and helium ions are implanted into the second depth Z2. In S3504, after implanting hydrogen ions, the semiconductor substrate 10 is heat-treated to diffuse hydrogen ions and helium ions. A collector electrode forming step S3506 may be performed after the lower surface side structure forming step.
　図３６は、下面側構造形成段階において、第１の深さＺ１に水素イオンを注入し、第２の深さＺ２にヘリウムイオンを注入する工程の他の例を示す。本例においては、第１の深さＺ１への水素イオンの注入および熱処理は、カソード領域形成段階Ｓ３５０３で行う。また、第２の深さＺ２へのヘリウムイオンの注入および熱処理は、バッファ領域形成段階Ｓ３５０６で行う。 FIG. 36 shows another example of the step of implanting hydrogen ions to the first depth Z1 and implanting helium ions to the second depth Z2 in the lower surface side structure formation step. In this example, the implantation of hydrogen ions to the first depth Z1 and the heat treatment are performed in the cathode region forming step S3503. Further, the implantation of helium ions to the second depth Z2 and the heat treatment are performed in the buffer region forming step S3506.
　下面側構造形成段階は、トレンチ部等の上面側構造形成段階Ｓ３５００よりも後に行ってよい。本例の下面側構造形成段階は、カソード領域形成段階Ｓ３５０３と、バッファ領域形成段階Ｓ３５０４を有する。図３６では、下面側構造形成段階の他の段階を省略している。 The lower surface side structure forming step may be performed after the upper surface side structure forming step S3500 such as the trench portion. The lower surface side structure forming step of this example includes a cathode area forming step S3503 and a buffer area forming step S3504. In FIG. 36, the other steps of the lower surface side structure forming step are omitted.
　本例の半導体装置１００は、トランジスタ部７０とダイオード部８０を備えてよい。この場合、下面２３の全体にカソード領域８２を形成した後に、Ｐ型ドーパントを選択的に注入することで、カソード領域８２の一部にＰ型のコレクタ領域２２を形成してよい。カソード領域形成段階Ｓ３５０３においては、リン等のＮ型ドーパントを含むＰＨ３等の原料ガスを用いてよい。カソード領域形成段階Ｓ３５０３において、下面２３の全体に、第１の深さＺ１に水素イオンが注入される。 The semiconductor device 100 of this example may include a transistor section 70 and a diode section 80. In this case, the P-type collector region 22 may be formed in a part of the cathode region 82 by selectively implanting the P-type dopant after forming the cathode region 82 on the entire lower surface 23. In the cathode region forming step S3503, a source gas such as PH3 containing an N-type dopant such as phosphorus may be used. In the cathode region forming step S3503, hydrogen ions are implanted into the entire lower surface 23 to the first depth Z1.
　また、下面２３にコレクタ領域２２を選択的に形成した後に、下面２３の全体にＮ型ドーパントと水素イオンを注入してカソード領域８２を形成してもよい。この場合、コレクタ領域２２には、導電型がＮ型に反転しないように、予め高濃度のＰ型ドーパントが注入されてよい。このような工程により、第１の深さＺ１は、コレクタ領域２２およびカソード領域８２に配置される。 Alternatively, the cathode region 82 may be formed by selectively forming the collector region 22 on the lower surface 23 and then implanting an N-type dopant and hydrogen ions into the entire lower surface 23. In this case, the collector region 22 may be preliminarily implanted with a high concentration of P-type dopant so that the conductivity type is not inverted to N-type. By such a step, the first depth Z1 is arranged in the collector region 22 and the cathode region 82.
　なお、半導体装置１００がトランジスタ部７０を備えず、ダイオード部８０を備える場合、コレクタ領域２２を形成する工程は省略できる。また、第２の深さＺ２への水素注入は、バッファ領域２０を形成する段階で行ってよい。下面側構造形成段階の後に、コレクタ電極形成段階Ｓ３５０６を行ってよい。 If the semiconductor device 100 does not have the transistor section 70 but the diode section 80, the step of forming the collector region 22 can be omitted. Further, hydrogen implantation to the second depth Z2 may be performed at the stage of forming the buffer region 20. A collector electrode forming step S3506 may be performed after the lower surface side structure forming step.
　以上、本発明を実施の形態を用いて説明したが、本発明の技術的範囲は上記実施の形態に記載の範囲には限定されない。上記実施の形態に、多様な変更または改良を加えることが可能であることが当業者に明らかである。その様な変更または改良を加えた形態も本発明の技術的範囲に含まれ得ることが、請求の範囲の記載から明らかである。 The present invention has been described above using the embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is apparent to those skilled in the art that various changes or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.
　請求の範囲、明細書、および図面中において示した装置、システム、プログラム、および方法における動作、手順、ステップ、および段階等の各処理の実行順序は、特段「より前に」、「先立って」等と明示しておらず、また、前の処理の出力を後の処理で用いるのでない限り、任意の順序で実現しうることに留意すべきである。請求の範囲、明細書、および図面中の動作フローに関して、便宜上「まず、」、「次に、」等を用いて説明したとしても、この順で実施することが必須であることを意味するものではない。 The execution order of each process such as the operation, procedure, step, and stage in the device, system, program, and method shown in the claims, the specification, and the drawings is "preceding" or "prior to". It should be noted that the output of the previous process can be realized in any order unless explicitly stated otherwise. Even if the description of the claims, the description, and the operation flow in the drawings are made by using “first,” “next,” and the like for convenience, it means that it is essential to carry out in this order. is not.
１０・・・半導体基板、１１・・・ウェル領域、１２・・・エミッタ領域、１４・・・ベース領域、１５・・・コンタクト領域、１６・・・蓄積領域、１８・・・ドリフト領域、２０・・・バッファ領域、２１・・・上面、２２・・・コレクタ領域、２３・・・下面、２４、２５・・・ピーク、３０・・・ダミートレンチ部、３２・・・ダミー絶縁膜、３４・・・ダミー導電部、３８・・・層間絶縁膜、４０・・・ゲートトレンチ部、４２・・・ゲート絶縁膜、４４・・・ゲート導電部、４８・・・ゲートランナー、５０・・・ゲート金属層、５２・・・エミッタ電極、５４・・・コレクタ電極、７０・・・トランジスタ部、７２・・・境界部、８０・・・ダイオード部、８２・・・カソード領域、９０・・・エッジ終端構造部、９２・・・ガードリング、９４・・・フィールドプレート、１００・・・半導体装置、１０６・・・通過領域、１１１・・・第１のドナー濃度ピーク、１１２、１２２、１３２、１４２、１７２・・・上りスロープ、１１３、１２３、１３３、１４３、１７３・・・下りスロープ、１１４、１２４、１２５、１３４、１４４、１４５・・・傾き、１１６・・・ゲートパッド、１１８・・・エミッタパッド、１２０・・・活性部、１２１・・・第２のドナー濃度ピーク、１３１・・・水素濃度ピーク、１４０・・・外周端、１４１・・・ヘリウム濃度ピーク、１５０・・・平坦領域、１５１・・・谷、１６１・・・第１の例、１６２・・・第２の例、１６３・・・第３の例、１６４・・・第４の例、１６５・・・第５の例、１７１・・・空孔濃度ピーク、１７４・・・チャネルストッパ、１７５・・・空孔欠陥濃度分布、１８０・・・ベースドーピング領域、１８１・・・ノンドーピング領域、１８２・・・保護膜、１８４・・・めっき層、１９０・・・中間境界領域、１９２・・・ライフタイム制御領域、１９４・・・水素濃度ピーク、１９６・・・アルゴン濃度ピーク、２００・・・フォトレジスト膜 10... Semiconductor substrate, 11... Well region, 12... Emitter region, 14... Base region, 15... Contact region, 16... Storage region, 18... Drift region, 20 ... buffer area, 21... upper surface, 22... collector area, 23... lower surface, 24, 25... peak, 30... dummy trench portion, 32... dummy insulating film, 34 ... Dummy conductive part, 38... Interlayer insulating film, 40... Gate trench part, 42... Gate insulating film, 44... Gate conductive part, 48... Gate runner, 50... Gate metal layer, 52... Emitter electrode, 54... Collector electrode, 70... Transistor section, 72... Border section, 80... Diode section, 82... Cathode region, 90... Edge termination structure, 92... Guard ring, 94... Field plate, 100... Semiconductor device, 106... Passage region, 111... First donor concentration peak, 112, 122, 132, 142, 172... Uphill slope, 113, 123, 133, 143, 173... Downhill slope, 114, 124, 125, 134, 144, 145... Inclination, 116... Gate pad, 118... -Emitter pad, 120... Active part, 121... Second donor concentration peak, 131... Hydrogen concentration peak, 140... Perimeter edge, 141... Helium concentration peak, 150... Flat Regions, 151... Valleys, 161... First example, 162... Second example, 163... Third example, 164... Fourth example, 165... Fifth , 171... Vacancy peak, 174... Channel stopper, 175... Vacancy concentration distribution, 180... Base doping region, 181... Non-doping region, 182... Protection Film, 184... Plating layer, 190... Intermediate boundary area, 192... Lifetime control area, 194... Hydrogen concentration peak, 196... Argon concentration peak, 200... Photoresist film

Claims (26)

  1. 　上面および下面を有する半導体基板を備える半導体装置であって、
    　前記半導体基板の前記上面と前記下面とを結ぶ深さ方向において、水素濃度分布が水素濃度ピークを有し、ヘリウム濃度分布がヘリウム濃度ピークを有し、ドナー濃度分布が第１のドナー濃度ピークと第２のドナー濃度ピークを有し、
    　前記水素濃度ピークと前記第１のドナー濃度ピークは第１の深さに配置されており、前記ヘリウム濃度ピークと前記第２のドナー濃度ピークは、前記下面を基準として前記第１の深さよりも深い第２の深さに配置されており、
    　それぞれの濃度ピークは、前記下面から前記上面に向かうにつれて濃度値が増大する上りスロープを有し、
    　前記第２のドナー濃度ピークの前記上りスロープの傾きを、前記ヘリウム濃度ピークの前記上りスロープの傾きで規格化した値が、前記第１のドナー濃度ピークの前記上りスロープの傾きを、前記水素濃度ピークの前記上りスロープの傾きで規格化した値よりも小さい半導体装置。     A semiconductor device comprising a semiconductor substrate having an upper surface and a lower surface,
    In the depth direction connecting the upper surface and the lower surface of the semiconductor substrate, the hydrogen concentration distribution has a hydrogen concentration peak, the helium concentration distribution has a helium concentration peak, and the donor concentration distribution has a first donor concentration peak. Has a second donor concentration peak,
    The hydrogen concentration peak and the first donor concentration peak are arranged at a first depth, and the helium concentration peak and the second donor concentration peak are located below the first depth with respect to the lower surface. It is located at a deep second depth,
    Each concentration peak has an upward slope in which the concentration value increases from the lower surface toward the upper surface,
    A value obtained by normalizing the slope of the ascending slope of the second donor concentration peak by the slope of the ascending slope of the helium concentration peak gives the slope of the ascending slope of the first donor concentration peak as the hydrogen concentration. A semiconductor device that is smaller than a value standardized by the slope of the upward slope of the peak.
  2. 　それぞれの濃度ピークは、前記下面から前記上面に向かうにつれて濃度値が減少する下りスロープを有し、
    　前記ヘリウム濃度ピークは、前記上りスロープの傾きが、前記下りスロープの傾きよりも小さい
    　請求項１に記載の半導体装置。     Each concentration peak has a downward slope whose concentration value decreases from the lower surface toward the upper surface,
    The semiconductor device according to claim 1, wherein the helium concentration peak has a slope of the ascending slope smaller than a slope of the descending slope.
  3. 　それぞれの濃度ピークは、前記下面から前記上面に向かうにつれて濃度値が減少する下りスロープを有し、
    　前記第２のドナー濃度ピークは、前記上りスロープの傾きが、前記下りスロープの傾きよりも小さい
    　請求項１に記載の半導体装置。     Each concentration peak has a downward slope whose concentration value decreases from the lower surface toward the upper surface,
    The semiconductor device according to claim 1, wherein the slope of the ascending slope of the second donor concentration peak is smaller than the slope of the descending slope.
  4. 　前記第１の深さと前記第２の深さとの間における前記ドナー濃度分布は、ドナー濃度がほぼ一定の平坦領域を有し、
    　前記平坦領域の前記深さ方向における長さが、前記半導体基板の前記深さ方向における厚みの１０％以上である
    　請求項１から３のいずれか一項に記載の半導体装置。     The donor concentration distribution between the first depth and the second depth has a flat region where the donor concentration is substantially constant,
    The semiconductor device according to claim 1, wherein a length of the flat region in the depth direction is 10% or more of a thickness of the semiconductor substrate in the depth direction.
  5. 　前記第１の深さと前記第２の深さとの間における前記ドナー濃度分布は、ドナー濃度がほぼ一定の平坦領域を有し、
    　前記平坦領域の前記深さ方向における長さが１０μｍ以上である
    　請求項１から３のいずれか一項に記載の半導体装置。     The donor concentration distribution between the first depth and the second depth has a flat region where the donor concentration is substantially constant,
    The semiconductor device according to claim 1, wherein a length of the flat region in the depth direction is 10 μm or more.
  6. 　前記平坦領域のドナー濃度の最小値は、前記半導体基板のドナー濃度よりも高い
    　請求項４または５に記載の半導体装置。     The semiconductor device according to claim 4, wherein a minimum donor concentration of the flat region is higher than a donor concentration of the semiconductor substrate.
  7. 　前記第１の深さと前記第２の深さとの間におけるドナー濃度の最小値は、前記半導体基板のドナー濃度よりも高い
    　請求項６に記載の半導体装置。     The semiconductor device according to claim 6, wherein the minimum value of the donor concentration between the first depth and the second depth is higher than the donor concentration of the semiconductor substrate.
  8. 　前記ヘリウム濃度ピークの濃度値が、前記水素濃度ピークの濃度値よりも小さい
    　請求項１から７のいずれか一項に記載の半導体装置。     The semiconductor device according to claim 1, wherein a concentration value of the helium concentration peak is smaller than a concentration value of the hydrogen concentration peak.
  9. 　前記半導体基板に設けられたＮ型のドリフト領域と、
    　前記半導体基板において前記上面に接して設けられ、前記ドリフト領域よりもドナー濃度の高いエミッタ領域と、
    　前記エミッタ領域と前記ドリフト領域との間に設けられたＰ型のベース領域と、
    　前記半導体基板において前記下面に接して設けられたＰ型のコレクタ領域と、
    　前記コレクタ領域と前記ドリフト領域との間に設けられ、前記ドリフト領域よりもドナー濃度の高い１つ以上のドナー濃度ピークを有するＮ型のバッファ領域と
    　を更に備え、
    　前記第１のドナー濃度ピークは、前記バッファ領域の前記ドナー濃度ピークである
    　請求項１から８のいずれか一項に記載の半導体装置。     An N-type drift region provided on the semiconductor substrate,
    An emitter region provided in contact with the upper surface of the semiconductor substrate and having a donor concentration higher than that of the drift region;
    A P-type base region provided between the emitter region and the drift region,
    A P-type collector region provided in contact with the lower surface of the semiconductor substrate,
    An N-type buffer region provided between the collector region and the drift region, the N-type buffer region having one or more donor concentration peaks having a donor concentration higher than that of the drift region,
    The semiconductor device according to claim 1, wherein the first donor concentration peak is the donor concentration peak of the buffer region.
  10. 　前記ベース領域と前記ドリフト領域との間に設けられ、前記ドリフト領域よりもドナー濃度の高い１つ以上のドナー濃度ピークを有する蓄積領域を更に備え、
    　前記第２のドナー濃度ピークは、前記蓄積領域の前記ドナー濃度ピークである
    　請求項９に記載の半導体装置。     A storage region provided between the base region and the drift region, the storage region having one or more donor concentration peaks having a higher donor concentration than the drift region,
    The semiconductor device according to claim 9, wherein the second donor concentration peak is the donor concentration peak of the accumulation region.
  11. 　前記蓄積領域は、前記第２のドナー濃度ピーク以外に、水素以外のドナーによる前記ドナー濃度ピークを有する
    　請求項１０に記載の半導体装置。     The semiconductor device according to claim 10, wherein the accumulation region has the donor concentration peak due to a donor other than hydrogen, in addition to the second donor concentration peak.
  12. 　前記ベース領域と前記ドリフト領域との間に設けられ、前記ドリフト領域よりもドナー濃度の高い１つ以上のドナー濃度ピークを有する蓄積領域を更に備え、
    　前記第２のドナー濃度ピークは、前記バッファ領域と前記蓄積領域との間に配置されている
    　請求項９に記載の半導体装置。     A storage region provided between the base region and the drift region, the storage region having one or more donor concentration peaks having a higher donor concentration than the drift region,
    The semiconductor device according to claim 9, wherein the second donor concentration peak is arranged between the buffer region and the accumulation region.
  13. 　前記半導体基板の前記上面に設けられたゲートトレンチ部を更に備え、
    　前記第２のドナー濃度ピークは、前記ゲートトレンチ部の底部と、前記半導体基板の前記上面との間に配置されている
    　請求項１から１１のいずれか一項に記載の半導体装置。     Further comprising a gate trench portion provided on the upper surface of the semiconductor substrate,
    The semiconductor device according to claim 1, wherein the second donor concentration peak is arranged between a bottom portion of the gate trench portion and the upper surface of the semiconductor substrate.
  14. 　前記半導体基板に設けられた活性部と、
    　前記半導体基板の上面視において前記活性部を囲んで設けられたエッジ終端構造部と
    　を更に備え、
    　前記半導体基板は、前記ヘリウム濃度ピークの位置に注入されたヘリウムが通過した通過領域を有し、
    　前記深さ方向において、前記エッジ終端構造部に設けられた前記通過領域は、前記活性部に設けられた前記通過領域よりも短いか、または、前記エッジ終端構造部には前記通過領域が設けられていない
    　請求項１から１３のいずれか一項に記載の半導体装置。     An active portion provided on the semiconductor substrate;
    And an edge termination structure portion provided so as to surround the active portion in a top view of the semiconductor substrate,
    The semiconductor substrate has a passage region through which the injected helium has passed at the position of the helium concentration peak,
    In the depth direction, the passage area provided in the edge termination structure is shorter than the passage area provided in the active portion, or the passage area is provided in the edge termination structure. The semiconductor device according to claim 1, which is not provided.
  15. 　前記半導体基板に設けられたトランジスタ部およびダイオード部を更に備え、
    　前記半導体基板は、前記ヘリウム濃度ピークの位置に注入されたヘリウムが通過した通過領域を有し、
    　前記深さ方向において、前記ダイオード部に設けられた前記通過領域は、前記トランジスタ部に設けられた前記通過領域よりも短いか、または、前記ダイオード部には前記通過領域が設けられていない
    　請求項１から１４のいずれか一項に記載の半導体装置。     Further comprising a transistor portion and a diode portion provided on the semiconductor substrate,
    The semiconductor substrate has a passage region through which the injected helium has passed at the position of the helium concentration peak,
    In the depth direction, the passage region provided in the diode unit is shorter than the passage region provided in the transistor unit, or the diode unit is not provided with the passage region. 15. The semiconductor device according to any one of 1 to 14.
  16. 　前記半導体基板に設けられたトランジスタ部およびダイオード部を更に備え、
    　前記半導体基板は、前記ヘリウム濃度ピークの位置に注入されたヘリウムが通過した通過領域を有し、
    　前記深さ方向において、前記トランジスタ部に設けられた前記通過領域は、前記ダイオード部に設けられた前記通過領域よりも短いか、または、前記トランジスタ部には前記通過領域が設けられていない
    　請求項１から１４のいずれか一項に記載の半導体装置。     Further comprising a transistor portion and a diode portion provided on the semiconductor substrate,
    The semiconductor substrate has a passage region through which the injected helium has passed at the position of the helium concentration peak,
    In the depth direction, the passage region provided in the transistor unit is shorter than the passage region provided in the diode unit, or the transistor unit is not provided with the passage region. 15. The semiconductor device according to any one of 1 to 14.
  17. 　前記第１の深さが、前記下面から前記深さ方向に５μｍ以下の範囲に含まれている
    　請求項１から１５のいずれか一項に記載の半導体装置。     The semiconductor device according to claim 1, wherein the first depth is included in a range of 5 μm or less from the lower surface in the depth direction.
  18. 　前記水素濃度ピークにおけるドナー濃度が、１×１０１５／ｃｍ３以上、１×１０１７／ｃｍ３以下である
    　請求項１７に記載の半導体装置。     The semiconductor device according to claim 17, wherein the donor concentration at the hydrogen concentration peak is 1×10 15 /cm 3 or more and 1×10 17 /cm 3 or less.
  19. 　上面および下面を有する半導体基板を備える半導体装置であって、
    　前記半導体基板の前記上面と前記下面とを結ぶ深さ方向における水素濃度分布が、前記下面から前記深さ方向に５μｍ以下の範囲に配置された水素濃度ピークと、前記水素濃度ピークよりも前記上面側に配置されたヘリウム濃度ピークとを有する半導体装置。     A semiconductor device comprising a semiconductor substrate having an upper surface and a lower surface,
    The hydrogen concentration distribution in the depth direction connecting the upper surface and the lower surface of the semiconductor substrate is located within a range of 5 μm or less from the lower surface in the depth direction, and the upper surface is higher than the hydrogen concentration peak. A semiconductor device having a helium concentration peak disposed on the side.
  20. 　前記下面と前記水素濃度ピークの間に不純物濃度ピークを有し、前記不純物濃度ピークの不純物はアルゴンまたはフッ素である
    　請求項１９に記載の半導体装置。     The semiconductor device according to claim 19, wherein an impurity concentration peak is provided between the lower surface and the hydrogen concentration peak, and the impurity of the impurity concentration peak is argon or fluorine.
  21. 　請求項１から１８のいずれか一項に記載の半導体装置の製造方法であって、
    　前記半導体基板の前記下面から前記第１の深さに水素を注入する第１注入段階と、
    　前記半導体基板の前記下面から前記第２の深さにヘリウムを注入して、前記ヘリウムが通過した通過領域を形成する第２注入段階と、
    　前記半導体基板を熱処理して、前記第１の深さに注入された水素を、前記通過領域に拡散させる拡散段階と
    　を備え、
    　前記拡散段階において熱処理された前記半導体基板において、前記通過領域のドナー濃度の最小値が、前記水素を注入する前の前記半導体基板のドナー濃度よりも高くなるように、前記第１注入段階における水素のドーズ量を定める製造方法。     The method of manufacturing a semiconductor device according to claim 1, wherein
    A first implanting step of implanting hydrogen from the lower surface of the semiconductor substrate to the first depth;
    A second implantation step of implanting helium from the lower surface of the semiconductor substrate to the second depth to form a passage region through which the helium has passed;
    A heat treatment of the semiconductor substrate to diffuse the hydrogen implanted at the first depth into the passage region.
    In the semiconductor substrate heat-treated in the diffusion step, hydrogen in the first implanting step is performed so that a minimum donor concentration of the passing region is higher than a donor concentration of the semiconductor substrate before implanting the hydrogen. Manufacturing method that determines the dose amount of.
  22. 　前記第１注入段階では、前記半導体基板における水素の拡散係数と、前記第２の深さから定まる最小ドーズ量以上のドーズ量で、水素を注入する
    　請求項２１に記載の製造方法。     22. The manufacturing method according to claim 21, wherein in the first implanting step, hydrogen is implanted with a dose amount equal to or larger than a minimum dose amount determined from the diffusion coefficient of hydrogen in the semiconductor substrate and the second depth.
  23. 　前記半導体基板はシリコン基板であり、前記下面からの前記第２の深さをｘ（μm）とした場合に、前記第１注入段階における水素のドーズ量Ｑ（ｉｏｎｓ／ｃｍ２）が下式を満たす
    　Ｑ≧１．６４９１×１０１３×ｅ０．０６１６１９ｘ
    　請求項２１または２２に記載の製造方法。     The semiconductor substrate is a silicon substrate, and when the second depth from the lower surface is x (μm), the hydrogen dose Q (ions/cm 2 ) in the first implantation step is expressed by the following formula. Satisfy Q≧1.6491×10 13 ×e 0.061619x
    The manufacturing method according to claim 21 or 22.
  24. 　前記第１注入段階において、プラズマドーピングにより、前記第１の深さに水素を注入する
    　請求項２１から２３のいずれか一項に記載の製造方法。     24. The manufacturing method according to claim 21, wherein hydrogen is injected to the first depth by plasma doping in the first injection step.
  25. 　前記プラズマドーピングの後に、前記半導体基板の前記下面を研削する
    　請求項２４に記載の製造方法。     The manufacturing method according to claim 24, wherein the lower surface of the semiconductor substrate is ground after the plasma doping.
  26. 　前記プラズマドーピングの後に、前記半導体基板の前記下面をレーザーアニールする
    　請求項２４に記載の製造方法。     The manufacturing method according to claim 24, wherein the lower surface of the semiconductor substrate is laser-annealed after the plasma doping.
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